diff --git a/syntax/asm_ca65.vim b/syntax/asm_ca65.vim
index 7d984ce..583b0d2 100644
--- a/syntax/asm_ca65.vim
+++ b/syntax/asm_ca65.vim
@@ -248,8 +248,9 @@ syn region asm_ca65String   start=+"+ skip=+\\"+ end=+"+
 syn region asm_ca65Char     start=+'+ skip=+\\'+ end=+'+
 
 " Line comments
-syn match asm_ca65Comment   ";.*" contains=asm_ca65Todo
-syn keyword asm_ca65Todo    contained TODO FIXME XXX HACK
+syn match asm_ca65Comment ";.*" contains=asm_ca65Todo,@Spell
+syn region asm_ca65Comment matchgroup=asm_ca65CCommentStart start="/\*" end="\*/" contains=asm_ca65Todo,@Spell fold extend
+syn keyword asm_ca65Todo contained TODO FIXME XXX HACK
 
 syn case match
 
@@ -264,6 +265,7 @@ if version >= 508 || !exists("did_asm_ca65_syntax_inits")
     command -nargs=+ HiLink hi def link <args>
   endif
 
+  HiLink asm_ca65CCommentStart Comment
   HiLink asm_ca65Comment    Comment
   HiLink asm_ca65Todo       Todo
   HiLink asm_ca65Mnemonic   Keyword