diff --git a/syntax/c.vim b/syntax/c.vim
index 45b9d1d..984cdc3 100644
--- a/syntax/c.vim
+++ b/syntax/c.vim
@@ -383,7 +383,8 @@ if !exists("c_no_if0")
 endif
 syn region	cIncluded	display contained start=+"+ skip=+\\\\\|\\"+ end=+"+
 syn match	cIncluded	display contained "<[^>]*>"
-syn match	cInclude	display "^\s*\zs\(%:\|#\)\s*include\>\s*["<]" contains=cIncluded
+syn match	cIncluded	display contained "[a-zA-Z_][a-zA-Z0-9_]*"
+syn match	cInclude	display "^\s*\zs\(%:\|#\)\s*include\>\s*["<a-zA-Z]" contains=cIncluded
 "syn match cLineSkip	"\\$"
 syn cluster	cPreProcGroup	contains=cPreCondit,cIncluded,cInclude,cDefine,cErrInParen,cErrInBracket,cUserLabel,cSpecial,cOctalZero,cCppOutWrapper,cCppInWrapper,@cCppOutInGroup,cFormat,cNumber,cFloat,cOctal,cOctalError,cNumbersCom,cString,cCommentSkip,cCommentString,cComment2String,@cCommentGroup,cCommentStartError,cParen,cBracket,cMulti,cBadBlock
 syn region	cDefine		start="^\s*\zs\(%:\|#\)\s*\(define\|undef\)\>" skip="\\$" end="$" keepend contains=ALLBUT,@cPreProcGroup,@Spell