diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,9 @@
 # Changelog for interval-algebra
 
+## 1.1.0
+
+* Fixes bug in `parseInterval`. For example, `parseInterval 0 0` parsed to a `Right (Interval (0, 0))`. Oops, the inequality of the should have been `y <= x` not `y < x`. This was fixed and a test added catch this error.
+
 ## 1.0.1
 
 * Adds `beginervalMoment` and `endervalMoment` functions to create intervals of moment duration from a begin or end.
diff --git a/interval-algebra.cabal b/interval-algebra.cabal
--- a/interval-algebra.cabal
+++ b/interval-algebra.cabal
@@ -1,6 +1,6 @@
 cabal-version:  2.2
 name:           interval-algebra
-version:        1.0.1
+version:        1.1.0
 synopsis:       An implementation of Allen's interval algebra for temporal logic
 description:    Please see the README on GitHub at <https://github.com/novisci/interval-algebra>
 category:       Algebra,Time
diff --git a/src/IntervalAlgebra/Core.hs b/src/IntervalAlgebra/Core.hs
--- a/src/IntervalAlgebra/Core.hs
+++ b/src/IntervalAlgebra/Core.hs
@@ -237,8 +237,8 @@
 -- 
 parseInterval :: (Show a, Ord a) => a -> a -> Either ParseErrorInterval (Interval a)
 parseInterval x y
-    |  y < x    = Left  $ ParseErrorInterval $ show y ++ "<" ++ show x
-    | otherwise = Right $ Interval (x, y)
+    | x < y     = Right $ Interval (x, y) 
+    | otherwise = Left  $ ParseErrorInterval $ show y ++ "<=" ++ show x
 
 intervalBegin :: (Ord a) => Interval a -> a
 intervalBegin (Interval x) = fst x
diff --git a/test/IntervalAlgebraSpec.hs b/test/IntervalAlgebraSpec.hs
--- a/test/IntervalAlgebraSpec.hs
+++ b/test/IntervalAlgebraSpec.hs
@@ -90,7 +90,9 @@
       it "endervalMoment duration is moment" $ moment' (endervalMoment (26::Int)) `shouldBe` (1 :: Int)
 
       it "parsing fails on bad inputs" $ 
-         parseInterval 10 0 `shouldBe` Left (IA.ParseErrorInterval "0<10")
+         parseInterval 10 0 `shouldBe` Left (IA.ParseErrorInterval "0<=10")
+      it "parsing fails on bad inputs" $ 
+         parseInterval 0 0 `shouldBe` Left (IA.ParseErrorInterval "0<=0")
       it "parsing works on good inputs" $
          parseInterval 0 10 `shouldBe` Right (beginerval 10 (0::Int))