diff --git a/geval.cabal b/geval.cabal
index 0bf6348..52bd563 100644
--- a/geval.cabal
+++ b/geval.cabal
@@ -1,5 +1,5 @@
 name:                geval
-version:             0.5.2.0
+version:             0.5.3.0
 synopsis:            Machine learning evaluation tools
 description:         Please see README.md
 homepage:            http://github.com/name/project
diff --git a/src/GEval/Core.hs b/src/GEval/Core.hs
index ba8d734..219db1e 100644
--- a/src/GEval/Core.hs
+++ b/src/GEval/Core.hs
@@ -79,7 +79,7 @@ defaultLogLossHashedSize :: Word32
 defaultLogLossHashedSize = 10
 
 data Metric = RMSE | MSE | BLEU | Accuracy | ClippEU | FMeasure Double | NMI | LogLossHashed Word32 | CharMatch
-              | MAP
+              | MAP | LogLoss
               deriving (Eq)
 
 instance Show Metric where
@@ -98,6 +98,7 @@ instance Show Metric where
                                                        (show nbOfBits))
   show CharMatch = "CharMatch"
   show MAP = "MAP"
+  show LogLoss = "LogLoss"
 
 instance Read Metric where
   readsPrec _ ('R':'M':'S':'E':theRest) = [(RMSE, theRest)]
@@ -112,6 +113,7 @@ instance Read Metric where
   readsPrec p ('L':'o':'g':'L':'o':'s':'s':'H':'a':'s':'h':'e':'d':theRest) = case readsPrec p theRest of
     [(nbOfBits, theRest)] -> [(LogLossHashed nbOfBits, theRest)]
     _ -> [(LogLossHashed defaultLogLossHashedSize, theRest)]
+  readsPrec _ ('L':'o':'g':'L':'o':'s':'s':theRest) = [(LogLoss, theRest)]
   readsPrec p ('C':'h':'a':'r':'M':'a':'t':'c':'h':theRest) = [(CharMatch, theRest)]
   readsPrec _ ('M':'A':'P':theRest) = [(MAP, theRest)]
 
@@ -128,6 +130,7 @@ getMetricOrdering NMI = TheHigherTheBetter
 getMetricOrdering (LogLossHashed _) = TheLowerTheBetter
 getMetricOrdering CharMatch = TheHigherTheBetter
 getMetricOrdering MAP = TheHigherTheBetter
+getMetricOrdering LogLoss = TheLowerTheBetter
 
 defaultOutDirectory = "."
 defaultTestName = "test-A"
@@ -295,6 +298,9 @@ gevalCore' :: (MonadIO m, MonadThrow m, MonadBaseControl IO m) => Metric -> Line
 gevalCore' MSE _ = gevalCoreWithoutInput outParser outParser itemError averageC id
   where outParser = getValue . TR.double
 
+gevalCore' LogLoss _ = gevalCoreWithoutInput outParser outParser itemLogLossError averageC id
+  where outParser = getValue . TR.double
+
 gevalCore' BLEU _ = gevalCoreWithoutInput (Right . Prelude.map Prelude.words . DLS.splitOn "\t" . unpack) (Right . Prelude.words . unpack) bleuCombine bleuAgg bleuFinal
   where bleuFinal (p1, p2, p3, p4, rl, l1, l2, l3, l4) = ((p1 /. l1) * (p2 /. l2) * (p3 /. l3) * (p4 /. l4)) ** 0.25 * (brevityPenalty l1 rl)
         bleuCombine (refs, sen) = bleuStep refs sen
@@ -490,6 +496,17 @@ items (LineSource lineSource _ _) parser =
 itemError :: (Double, Double) -> Double
 itemError (exp, out) = (exp-out)**2
 
+itemLogLossError :: (Double, Double) -> Double
+itemLogLossError (exp, out)
+  | exp' > 0.5 = - (log out')
+  | otherwise = - (log (1 - out'))
+  where exp' = normalizeAsProb exp
+        out' = normalizeAsProb out
+        normalizeAsProb v
+          | v >= 1.0 = 1.0
+          | v <= 0.0 = 0.0
+          | otherwise = v
+
 getValue :: Num a => Either String (a, Text) -> Either String a
 getValue (Right (x, reminder)) =
   if Data.Text.null reminder || Data.Text.head reminder == '\t'
diff --git a/src/GEval/CreateChallenge.hs b/src/GEval/CreateChallenge.hs
index 411f272..b0e53a5 100644
--- a/src/GEval/CreateChallenge.hs
+++ b/src/GEval/CreateChallenge.hs
@@ -160,6 +160,15 @@ See Christopher D. Manning, Prabhakar Raghavan and Hinrich Schütze,
 more discussion of the metric.
 |] ++ (commonReadmeMDContents testName)
 
+readmeMDContents LogLoss testName = [i|
+Give the probability of a positive sentiment
+============================================
+
+Give the probability that a sentence expresses a positive sentiment.
+
+This a sample challenge for the log-loss metric.
+
+|] ++ (commonReadmeMDContents testName)
 
 readmeMDContents _ testName = [i|
 GEval sample challenge
@@ -245,6 +254,11 @@ honour	GB	honor
 titbit	GB	smakołyk
 tidbit	US	smakołyk
 |]
+trainContents LogLoss = [hereLit|0.0	Hell, no!!!
+0.0	I hate this stuff
+1.0	Lekker!!!
+0.0	Boring, boring, boring
+|]
 trainContents _ = [hereLit|0.06	0.39	0	0.206
 1.00	1.00	1	0.017
 317.8	5.20	67	0.048
@@ -276,6 +290,10 @@ devInContents MAP = [hereLit|US	noc
 GB	wózek dziecięcy
 GB	wizualizować
 |]
+devInContents LogLoss = [hereLit|Great stuff!
+Boring stuff
+That's good
+|]
 devInContents _ = [hereLit|0.72	0	0.007
 9.54	62	0.054
 |]
@@ -305,6 +323,10 @@ devExpectedContents MAP = [hereLit|night	nite
 pram
 visualise
 |]
+devExpectedContents LogLoss = [hereLit|1.0
+0.0
+1.0
+|]
 devExpectedContents _ = [hereLit|0.82
 95.2
 |]
@@ -336,6 +358,10 @@ testInContents MAP = [hereLit|US	wózek dziecięcy
 GB	słoń
 US	słoń
 |]
+testInContents LogLoss = [hereLit|That's great, ha, ha, I love it!
+Super-duper!!
+That is incredibly boring.
+|]
 testInContents _ = [hereLit|1.52	2	0.093
 30.06	14	0.009
 |]
@@ -367,6 +393,10 @@ testExpectedContents MAP = [hereLit|trolley
 elephant
 elephant
 |]
+testExpectedContents LogLoss = [hereLit|1.0
+1.0
+0.0
+|]
 testExpectedContents _ = [hereLit|0.11
 17.2
 |]
diff --git a/src/GEval/OptionsParser.hs b/src/GEval/OptionsParser.hs
index 617d718..d5fe2f8 100644
--- a/src/GEval/OptionsParser.hs
+++ b/src/GEval/OptionsParser.hs
@@ -100,7 +100,7 @@ metricReader = option auto
                  <> value defaultMetric
                  <> showDefault
                  <> metavar "METRIC"
-                 <> help "Metric to be used - RMSE, MSE, Accuracy, F-measure (specify as F1, F2, F0.25, etc.), MAP, BLEU, NMI, ClippEU, LogLossHashed or CharMatch" )
+                 <> help "Metric to be used - RMSE, MSE, Accuracy, LogLoss, F-measure (specify as F1, F2, F0.25, etc.), MAP, BLEU, NMI, ClippEU, LogLossHashed or CharMatch" )
 
 runGEval :: [String] -> IO (Either (ParserResult GEvalOptions) (Maybe MetricValue))
 runGEval args = do
diff --git a/test/Spec.hs b/test/Spec.hs
index e522718..c190b4d 100644
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -175,6 +175,11 @@ main = hspec $ do
                                 ["one", "one"]) `shouldBeAlmost` 0.5
     it "simple test" $ do
       runGEvalTest "map-simple" `shouldReturnAlmost` 0.444444444
+  describe "LogLoss" $ do
+    it "simple" $ do
+      runGEvalTest "logloss-simple" `shouldReturnAlmost` 0.31824
+    it "perfect" $ do
+      runGEvalTest "logloss-perfect" `shouldReturnAlmost` 0.0
   describe "evaluating single lines" $ do
     it "RMSE" $ do
       gevalCoreOnSingleLines RMSE (LineInFile "stub1" 1 "blabla")
diff --git a/test/logloss-perfect/logloss-perfect-solution/test-A/out.tsv b/test/logloss-perfect/logloss-perfect-solution/test-A/out.tsv
new file mode 100644
index 0000000..56c3026
--- /dev/null
+++ b/test/logloss-perfect/logloss-perfect-solution/test-A/out.tsv
@@ -0,0 +1,5 @@
+1.0
+0
+0.0
+1
+0
diff --git a/test/logloss-perfect/logloss-perfect/config.txt b/test/logloss-perfect/logloss-perfect/config.txt
new file mode 100644
index 0000000..84fee6c
--- /dev/null
+++ b/test/logloss-perfect/logloss-perfect/config.txt
@@ -0,0 +1 @@
+--metric LogLoss
diff --git a/test/logloss-perfect/logloss-perfect/test-A/expected.tsv b/test/logloss-perfect/logloss-perfect/test-A/expected.tsv
new file mode 100644
index 0000000..d69e70b
--- /dev/null
+++ b/test/logloss-perfect/logloss-perfect/test-A/expected.tsv
@@ -0,0 +1,5 @@
+1
+0
+0
+1
+0
diff --git a/test/logloss-simple/logloss-simple-solution/test-A/out.tsv b/test/logloss-simple/logloss-simple-solution/test-A/out.tsv
new file mode 100644
index 0000000..6978be2
--- /dev/null
+++ b/test/logloss-simple/logloss-simple-solution/test-A/out.tsv
@@ -0,0 +1,4 @@
+0.7
+0
+0.0
+0.6
diff --git a/test/logloss-simple/logloss-simple/config.txt b/test/logloss-simple/logloss-simple/config.txt
new file mode 100644
index 0000000..84fee6c
--- /dev/null
+++ b/test/logloss-simple/logloss-simple/config.txt
@@ -0,0 +1 @@
+--metric LogLoss
diff --git a/test/logloss-simple/logloss-simple/test-A/expected.tsv b/test/logloss-simple/logloss-simple/test-A/expected.tsv
new file mode 100644
index 0000000..968ac3e
--- /dev/null
+++ b/test/logloss-simple/logloss-simple/test-A/expected.tsv
@@ -0,0 +1,4 @@
+1
+0
+0
+0