diff --git a/Ledger/Dates.hs b/Ledger/Dates.hs
new file mode 100644
index 000000000..85b14eee7
--- /dev/null
+++ b/Ledger/Dates.hs
@@ -0,0 +1,66 @@
+{-|
+
+Types for Dates and DateTimes, implemented in terms of UTCTime
+
+-}
+
+module Ledger.Dates(
+    Date,                    
+    DateTime,
+    mkDate,
+    mkDateTime,
+    parsedatetime,
+    parsedate,
+    datetimeToDate,
+    elapsedSeconds
+    ) where
+
+import Data.Time.Clock
+import Data.Time.Format
+import Data.Time.Calendar
+import Data.Time.LocalTime
+import System.Locale (defaultTimeLocale)
+import Text.Printf
+import Data.Maybe
+
+newtype Date = Date UTCTime
+    deriving (Ord, Eq)
+
+newtype DateTime = DateTime UTCTime
+    deriving (Ord, Eq)
+
+instance Show Date where
+   show (Date t) = formatTime defaultTimeLocale "%Y/%m/%d" t
+
+instance Show DateTime where 
+   show (DateTime t) = formatTime defaultTimeLocale "%Y/%m/%d %H:%M:%S" t
+
+mkDate :: Day -> Date
+mkDate day = Date (localTimeToUTC utc (LocalTime day midnight))
+
+mkDateTime :: Day -> TimeOfDay -> DateTime
+mkDateTime day tod = DateTime (localTimeToUTC utc (LocalTime day tod))
+
+-- | Parse a date-time string to a time type, or raise an error.
+parsedatetime :: String -> DateTime
+parsedatetime s = DateTime $
+    parsetimewith "%Y/%m/%d %H:%M:%S" s $
+    error $ printf "could not parse timestamp \"%s\"" s
+
+-- | Parse a date string to a time type, or raise an error.
+parsedate :: String -> Date
+parsedate s =  Date $
+    parsetimewith "%Y/%m/%d" s $
+    error $ printf "could not parse date \"%s\"" s
+
+-- | Parse a time string to a time type using the provided pattern, or
+-- return the default.
+parsetimewith :: ParseTime t => String -> String -> t -> t
+parsetimewith pat s def = fromMaybe def $ parseTime defaultTimeLocale pat s
+
+datetimeToDate :: DateTime -> Date
+datetimeToDate (DateTime (UTCTime{utctDay=day})) = Date (UTCTime day 0)
+
+elapsedSeconds :: Fractional a => DateTime -> DateTime -> a
+elapsedSeconds (DateTime dt1) (DateTime dt2) = realToFrac $ diffUTCTime dt1 dt2
+
diff --git a/Ledger/Entry.hs b/Ledger/Entry.hs
index 39324d9a6..eda52d45a 100644
--- a/Ledger/Entry.hs
+++ b/Ledger/Entry.hs
@@ -22,7 +22,7 @@ instance Show PeriodicEntry where
     show e = "~ " ++ (periodexpr e) ++ "\n" ++ unlines (map show (p_transactions e))
 
 nullentry = Entry {
-              edate="", 
+              edate=parsedate "1900/1/1", 
               estatus=False, 
               ecode="", 
               edescription="", 
@@ -67,7 +67,7 @@ showEntry e =
       showaccountname s = printf "%-34s" s
       showcomment s = if (length s) > 0 then "  ; "++s else ""
 
-showDate = printf "%-10s"
+showDate d = printf "%-10s" (show d)
 
 isEntryBalanced :: Entry -> Bool
 isEntryBalanced (Entry {etransactions=ts}) = 
diff --git a/Ledger/Parse.hs b/Ledger/Parse.hs
index 946438e50..75f030967 100644
--- a/Ledger/Parse.hs
+++ b/Ledger/Parse.hs
@@ -19,6 +19,8 @@ import Ledger.Amount
 import Ledger.Entry
 import Ledger.Commodity
 import Ledger.TimeLog
+import Data.Time.LocalTime
+import Data.Time.Calendar
 
 
 -- utils
@@ -233,15 +235,28 @@ ledgerentry = do
   transactions <- ledgertransactions
   return $ balanceEntry $ Entry date status code description comment transactions (unlines preceding)
 
-ledgerdate :: Parser String
-ledgerdate = do 
+ledgerday :: Parser Day
+ledgerday = do 
   y <- many1 digit
   char '/'
   m <- many1 digit
   char '/'
   d <- many1 digit
   many1 spacenonewline
-  return $ printf "%04s/%02s/%02s" y m d
+  return (fromGregorian (read y) (read m) (read d))
+
+ledgerdate :: Parser Date
+ledgerdate = fmap mkDate ledgerday
+
+ledgerdatetime :: Parser DateTime
+ledgerdatetime = do 
+  day <- ledgerday
+  h <- many1 digit
+  char ':'
+  m <- many1 digit
+  many1 spacenonewline
+  return (mkDateTime day (TimeOfDay (read h) (read m) 0))
+
 
 ledgerstatus :: Parser Bool
 ledgerstatus = try (do { char '*'; many1 spacenonewline; return True } ) <|> return False
@@ -452,9 +467,7 @@ timelogentry = do
   many (commentline <|> blankline)
   code <- oneOf "bhioO"
   many1 spacenonewline
-  date <- ledgerdate
-  time <- many $ oneOf "0123456789:"
-  let datetime = date ++ " " ++ time
+  datetime <- ledgerdatetime
   many spacenonewline
   comment <- restofline
   return $ TimeLogEntry code datetime comment
diff --git a/Ledger/RawLedger.hs b/Ledger/RawLedger.hs
index d6730d132..72845b473 100644
--- a/Ledger/RawLedger.hs
+++ b/Ledger/RawLedger.hs
@@ -43,7 +43,7 @@ rawLedgerAccountNameTree l = accountNameTreeFrom $ rawLedgerAccountNames l
 -- | Remove ledger entries we are not interested in.
 -- Keep only those which fall between the begin and end dates, and match
 -- the description pattern, and are cleared or real if those options are active.
-filterRawLedger :: Date -> Date -> [String] -> Bool -> Bool -> RawLedger -> RawLedger
+filterRawLedger :: Maybe Date -> Maybe Date -> [String] -> Bool -> Bool -> RawLedger -> RawLedger
 filterRawLedger begin end pats clearedonly realonly = 
     filterRawLedgerTransactionsByRealness realonly .
     filterRawLedgerEntriesByClearedStatus clearedonly .
@@ -59,14 +59,11 @@ filterRawLedgerEntriesByDescription pats (RawLedger ms ps es f) =
 -- | Keep only entries which fall between begin and end dates. 
 -- We include entries on the begin date and exclude entries on the end
 -- date, like ledger.  An empty date string means no restriction.
-filterRawLedgerEntriesByDate :: Date -> Date -> RawLedger -> RawLedger
+filterRawLedgerEntriesByDate :: Maybe Date -> Maybe Date -> RawLedger -> RawLedger
 filterRawLedgerEntriesByDate begin end (RawLedger ms ps es f) = 
     RawLedger ms ps (filter matchdate es) f
     where 
-      d1 = parsedate begin :: UTCTime
-      d2 = parsedate end
-      matchdate e = (null begin || d >= d1) && (null end || d < d2)
-                    where d = parsedate $ edate e
+      matchdate e = (maybe True (edate e>=) begin) && (maybe True (edate e<) end)
 
 -- | Keep only entries with cleared status, if the flag is true, otherwise
 -- do no filtering.
diff --git a/Ledger/TimeLog.hs b/Ledger/TimeLog.hs
index 96f0c1a2b..69a878b42 100644
--- a/Ledger/TimeLog.hs
+++ b/Ledger/TimeLog.hs
@@ -15,7 +15,7 @@ import Ledger.Amount
 
 
 instance Show TimeLogEntry where 
-    show t = printf "%s %s %s" (show $ tlcode t) (tldatetime t) (tlcomment t)
+    show t = printf "%s %s %s" (show $ tlcode t) (show $ tldatetime t) (tlcomment t)
 
 instance Show TimeLog where
     show tl = printf "TimeLog with %d entries" $ length $ timelog_entries tl
@@ -52,12 +52,11 @@ entryFromTimeLogInOut i o =
     }
     where
       acctname = tlcomment i
-      indate   = showdate intime
-      outdate  = showdate outtime
-      showdate = formatTime defaultTimeLocale "%Y/%m/%d"
-      intime   = parsedatetime $ tldatetime i
-      outtime  = parsedatetime $ tldatetime o
-      amount   = Mixed [hours $ realToFrac (diffUTCTime outtime intime) / 3600]
+      indate   = datetimeToDate intime
+      outdate  = datetimeToDate outtime
+      intime   = tldatetime i
+      outtime  = tldatetime o
+      amount   = Mixed [hours $ elapsedSeconds outtime intime / 3600]
       txns     = [RawTransaction acctname amount "" RegularTransaction
                  --,RawTransaction "assets:time" (-amount) "" RegularTransaction
                  ]
diff --git a/Ledger/Transaction.hs b/Ledger/Transaction.hs
index ab595c680..4c41df58e 100644
--- a/Ledger/Transaction.hs
+++ b/Ledger/Transaction.hs
@@ -17,7 +17,7 @@ import Ledger.Amount
 instance Show Transaction where show=showTransaction
 
 showTransaction :: Transaction -> String
-showTransaction (Transaction eno d desc a amt ttype) = unwords [d,desc,a,show amt,show ttype]
+showTransaction (Transaction eno d desc a amt ttype) = unwords [show d,desc,a,show amt,show ttype]
 
 -- | Convert a 'Entry' to two or more 'Transaction's. An id number
 -- is attached to the transactions to preserve their grouping - it should
@@ -32,4 +32,4 @@ accountNamesFromTransactions ts = nub $ map account ts
 sumTransactions :: [Transaction] -> MixedAmount
 sumTransactions = sum . map amount
 
-nulltxn = Transaction 0 "" "" "" nullamt RegularTransaction
+nulltxn = Transaction 0  (parsedate "1900/1/1") "" "" nullamt RegularTransaction
diff --git a/Ledger/Types.hs b/Ledger/Types.hs
index 6f8597802..de5f938c7 100644
--- a/Ledger/Types.hs
+++ b/Ledger/Types.hs
@@ -11,10 +11,6 @@ import Ledger.Utils
 import qualified Data.Map as Map
 
 
-type Date = String
-
-type DateTime = String
-
 type AccountName = String
 
 data Side = L | R deriving (Eq,Show) 
diff --git a/Ledger/Utils.hs b/Ledger/Utils.hs
index 97babfddb..dc534e3f9 100644
--- a/Ledger/Utils.hs
+++ b/Ledger/Utils.hs
@@ -11,15 +11,13 @@ module Data.List,
 --module Data.Map,
 module Data.Maybe,
 module Data.Ord,
-module Data.Time.Clock,
-module Data.Time.Format,
 module Data.Tree,
 module Debug.Trace,
 module Ledger.Utils,
-module System.Locale,
 module Text.Printf,
 module Text.Regex,
 module Test.HUnit,
+module Ledger.Dates,
 )
 where
 import Char
@@ -28,16 +26,14 @@ import Data.List
 --import qualified Data.Map as Map
 import Data.Maybe
 import Data.Ord
-import Data.Time.Clock (UTCTime, diffUTCTime)
-import Data.Time.Format (ParseTime, parseTime, formatTime)
 import Data.Tree
 import Debug.Trace
-import System.Locale (defaultTimeLocale)
 import Test.HUnit
 import Test.QuickCheck hiding (test, Testable)
 import Text.Printf
 import Text.Regex
 import Text.ParserCombinators.Parsec (parse)
+import Ledger.Dates
 
 
 elideLeft width s =
@@ -59,25 +55,6 @@ containsRegex r s = case matchRegex r s of
                       Just _ -> True
                       otherwise -> False
 
--- time
-
--- | Parse a date-time string to a time type, or raise an error.
-parsedatetime :: ParseTime t => String -> t
-parsedatetime s =
-    parsetimewith "%Y/%m/%d %H:%M:%S" s $
-    error $ printf "could not parse timestamp \"%s\"" s
-
--- | Parse a date string to a time type, or raise an error.
-parsedate :: ParseTime t => String -> t
-parsedate s = 
-    parsetimewith "%Y/%m/%d" s $
-    error $ printf "could not parse date \"%s\"" s
-
--- | Parse a time string to a time type using the provided pattern, or
--- return the default.
-parsetimewith :: ParseTime t => String -> String -> t -> t
-parsetimewith pat s def = fromMaybe def $ parseTime defaultTimeLocale pat s
-
 -- lists
 
 splitAtElement :: Eq a => a -> [a] -> [[a]]
diff --git a/RegisterCommand.hs b/RegisterCommand.hs
index 516ef4d6d..ee92ca7d7 100644
--- a/RegisterCommand.hs
+++ b/RegisterCommand.hs
@@ -46,7 +46,7 @@ showRegisterReport opts args l = showtxns ts nulltxn nullamt
       showtxn omitdesc t b = entrydesc ++ txn ++ bal ++ "\n"
           where
             entrydesc = if omitdesc then replicate 32 ' ' else printf "%s %s " date desc
-            date = showDate $ da
+            date = show $ da
             desc = printf "%-20s" $ elideRight 20 de :: String
             txn = showRawTransaction $ RawTransaction a amt "" tt
             bal = printf " %12s" (showMixedAmountOrZero b)
diff --git a/Tests.hs b/Tests.hs
index 4895d3058..7d791c181 100644
--- a/Tests.hs
+++ b/Tests.hs
@@ -274,7 +274,7 @@ entry1_str = "\
 \\n" --"
 
 entry1 =
-    (Entry "2007/01/28" False "" "coopportunity" ""
+    (Entry (parsedate "2007/01/28") False "" "coopportunity" ""
      [RawTransaction "expenses:food:groceries" (Mixed [dollars 47.18]) "" RegularTransaction, 
       RawTransaction "assets:checking" (Mixed [dollars (-47.18)]) "" RegularTransaction] "")
 
@@ -412,7 +412,7 @@ rawledger7 = RawLedger
           [] 
           [
            Entry {
-             edate="2007/01/01", 
+             edate= parsedate "2007/01/01", 
              estatus=False, 
              ecode="*", 
              edescription="opening balance", 
@@ -435,7 +435,7 @@ rawledger7 = RawLedger
            }
           ,
            Entry {
-             edate="2007/02/01", 
+             edate= parsedate "2007/02/01", 
              estatus=False, 
              ecode="*", 
              edescription="ayres suites", 
@@ -458,7 +458,7 @@ rawledger7 = RawLedger
            }
           ,
            Entry {
-             edate="2007/01/02", 
+             edate=parsedate "2007/01/02", 
              estatus=False, 
              ecode="*", 
              edescription="auto transfer to savings", 
@@ -481,7 +481,7 @@ rawledger7 = RawLedger
            }
           ,
            Entry {
-             edate="2007/01/03", 
+             edate=parsedate "2007/01/03", 
              estatus=False, 
              ecode="*", 
              edescription="poquito mas", 
@@ -504,7 +504,7 @@ rawledger7 = RawLedger
            }
           ,
            Entry {
-             edate="2007/01/03", 
+             edate=parsedate "2007/01/03", 
              estatus=False, 
              ecode="*", 
              edescription="verizon", 
@@ -527,7 +527,7 @@ rawledger7 = RawLedger
            }
           ,
            Entry {
-             edate="2007/01/03", 
+             edate=parsedate "2007/01/03", 
              estatus=False, 
              ecode="*", 
              edescription="discover", 
@@ -554,10 +554,10 @@ rawledger7 = RawLedger
 ledger7 = cacheLedger rawledger7 
 
 timelogentry1_str  = "i 2007/03/11 16:19:00 hledger\n"
-timelogentry1 = TimeLogEntry 'i' "2007/03/11 16:19:00" "hledger"
+timelogentry1 = TimeLogEntry 'i' (parsedatetime "2007/03/11 16:19:00") "hledger"
 
 timelogentry2_str  = "o 2007/03/11 16:30:00\n"
-timelogentry2 = TimeLogEntry 'o' "2007/03/11 16:30:00" ""
+timelogentry2 = TimeLogEntry 'o' (parsedatetime "2007/03/11 16:30:00") ""
 
 timelog1_str = concat [
                 timelogentry1_str,
diff --git a/Utils.hs b/Utils.hs
index 517b45541..dd1de7fe2 100644
--- a/Utils.hs
+++ b/Utils.hs
@@ -21,7 +21,7 @@ rawledgerfromfile f = do
 ledgerfromfile :: FilePath -> IO Ledger
 ledgerfromfile f = do
   l  <- rawledgerfromfile f
-  return $ cacheLedger $ filterRawLedger "" "" [] False False l
+  return $ cacheLedger $ filterRawLedger Nothing Nothing [] False False l
 
 -- | get a RawLedger from the file your LEDGER environment variable
 -- variable points to or (WARNING) an empty one if there was a problem.
@@ -35,7 +35,7 @@ myrawledger = do
 myledger :: IO Ledger
 myledger = do
   l <- myrawledger
-  return $ cacheLedger $ filterRawLedger "" "" [] False False l
+  return $ cacheLedger $ filterRawLedger Nothing Nothing [] False False l
 
 -- | get a named account from your ledger file
 myaccount :: AccountName -> IO Account
diff --git a/hledger.hs b/hledger.hs
index 916403103..128befbe4 100644
--- a/hledger.hs
+++ b/hledger.hs
@@ -64,6 +64,9 @@ main = do
        | cmd `isPrefixOf` "test"     = runtests args >> return ()
        | otherwise                   = putStr usage
 
+parsemaybedate "" = Nothing
+parsemaybedate s = Just (parsedate s)
+
 -- | parse the user's specified ledger file and do some action with it
 -- (or report a parse error). This function makes the whole thing go.
 parseLedgerAndDo :: [Opt] -> [String] -> ([Opt] -> [String] -> Ledger -> IO ()) -> IO ()
@@ -71,8 +74,8 @@ parseLedgerAndDo opts args cmd =
     ledgerFilePathFromOpts opts >>= parseLedgerFile >>= either printParseError runcmd
     where
       runcmd = cmd opts args . cacheLedger . setAmountDisplayPrefs . filterRawLedger b e dpats c r
-      b = beginDateFromOpts opts
-      e = endDateFromOpts opts
+      b = parsemaybedate (beginDateFromOpts opts)
+      e = parsemaybedate (endDateFromOpts opts)
       dpats = snd $ parseAccountDescriptionArgs args
       c = Cleared `elem` opts
       r = Real `elem` opts