diff --git a/syntax/haskell.vim b/syntax/haskell.vim
index f59a766..e1667a1 100644
--- a/syntax/haskell.vim
+++ b/syntax/haskell.vim
@@ -63,8 +63,8 @@ if get(g:, 'haskell_enable_static_pointers', 0)
   syn keyword haskellStatic static
 endif
 syn keyword haskellConditional if then else
-syn match haskellNumber "\<[0-9]\+\>\|\<0[xX][0-9a-fA-F]\+\>\|\<0[oO][0-7]\+\>\|\<0[bB][10]\+\>"
-syn match haskellFloat "\<[0-9]\+\.[0-9]\+\([eE][-+]\=[0-9]\+\)\=\>"
+syn match haskellNumber "\<[0-9]\+\>\|\<[0-9_]\+\>\|\<0[xX][0-9a-fA-F_]\+\>\|\<0[oO][0-7_]\+\>\|\<0[bB][10_]\+\>"
+syn match haskellFloat "\<[0-9]\+\.[0-9_]\+\([eE][-+]\=[0-9_]\+\)\=\>"
 syn match haskellSeparator  "[,;]"
 syn region haskellParens matchgroup=haskellDelimiter start="(" end=")" contains=TOP,haskellTypeSig,@Spell
 syn region haskellBrackets matchgroup=haskellDelimiter start="\[" end="]" contains=TOP,haskellTypeSig,@Spell