diff --git a/pandoc.cabal b/pandoc.cabal
index c2d771a91..f75b1a683 100644
--- a/pandoc.cabal
+++ b/pandoc.cabal
@@ -74,11 +74,11 @@ Library
                    Text.Pandoc.Writers.RTF,
                    Text.Pandoc.Writers.S5
   Other-Modules:   Text.Pandoc.XML
-  Ghc-Options:     -O2
+  Ghc-Options:     -O2 -Wall
   Ghc-Prof-Options: -auto-all
 
 Executable pandoc
   Hs-Source-Dirs:  .
   Main-Is:         Main.hs
-  Ghc-Options:     -O2
+  Ghc-Options:     -O2 -Wall
   Ghc-Prof-Options: -auto-all