diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # Changelog for the [`clash-vhdl`](http://hackage.haskell.org/package/clash-vhdl) package
 
+## 0.6.3 *November 12th 2015*
+* Fixes bugs:
+  * Do not generate overlapping literal patterns [#91](https://github.com/clash-lang/clash-compiler/issues/91)
+
 ## 0.6.2 *October 21st 2015*
 * New features:
   * Support `clash-prelude` 0.10.2
diff --git a/clash-vhdl.cabal b/clash-vhdl.cabal
--- a/clash-vhdl.cabal
+++ b/clash-vhdl.cabal
@@ -1,5 +1,5 @@
 Name:                 clash-vhdl
-Version:              0.6.2
+Version:              0.6.3
 Synopsis:             CAES Language for Synchronous Hardware - VHDL backend
 Description:
   CλaSH (pronounced ‘clash’) is a functional hardware description language that
diff --git a/src/CLaSH/Backend/VHDL.hs b/src/CLaSH/Backend/VHDL.hs
--- a/src/CLaSH/Backend/VHDL.hs
+++ b/src/CLaSH/Backend/VHDL.hs
@@ -28,7 +28,7 @@
 import           CLaSH.Netlist.BlackBox.Util          (extractLiterals, renderBlackBox)
 import           CLaSH.Netlist.Types
 import           CLaSH.Netlist.Util
-import           CLaSH.Util                           (clog2, curLoc, makeCached, (<:>))
+import           CLaSH.Util                           (clog2, curLoc, first, makeCached, on, (<:>))
 
 #ifdef CABAL
 import qualified Paths_clash_vhdl
@@ -447,8 +447,11 @@
 
 inst_ (CondAssignment id_ _ scrut scrutTy es) = fmap Just $
     "with" <+> parens (expr_ True scrut) <+> "select" <$>
-      indent 2 (text id_ <+> larrow <+> align (vcat (punctuate comma (conds es)) <> semi))
+      indent 2 (text id_ <+> larrow <+> align (vcat (punctuate comma (conds esNub)) <> semi))
   where
+    esMod = map (first (fmap (patMod scrutTy))) es
+    esNub = nubBy ((==) `on` fst) esMod
+
     conds :: [(Maybe Literal,Expr)] -> VHDLM [Doc]
     conds []                = return []
     conds [(_,e)]           = expr_ False e <+> "when" <+> "others" <:> return []
@@ -611,6 +614,10 @@
   in  parenIf (i' < 0) (integer i')
 patLit hwTy (NumLit i) = bits (toBits (conSize hwTy) i)
 patLit _    l          = exprLit Nothing l
+
+patMod :: HWType -> Literal -> Literal
+patMod hwTy (NumLit i) = NumLit (i `mod` (2 ^ typeSize hwTy))
+patMod _ l = l
 
 toBits :: Integral a => Int -> a -> [Bit]
 toBits size val = map (\x -> if odd x then H else L)