diff --git a/runtime/syntax/c.vim b/runtime/syntax/c.vim
index e24dbe3..5339ea6 100644
--- a/runtime/syntax/c.vim
+++ b/runtime/syntax/c.vim
@@ -1,7 +1,7 @@
 " Vim syntax file
 " Language:	C
 " Maintainer:	Bram Moolenaar <Bram@vim.org>
-" Last Change:	2006 Apr 05
+" Last Change:	2006 Apr 12
 
 " Quit when a (custom) syntax file was already loaded
 if exists("b:current_syntax")
@@ -30,7 +30,11 @@
   " cCppString: same as cString, but ends at end of line
   syn region	cCppString	start=+L\="+ skip=+\\\\\|\\"\|\\$+ excludenl end=+"+ end='$' contains=cSpecial,@Spell
 else
-  syn match	cFormat		display "%\(\d\+\$\)\=[-+' #0*]*\(\d*\|\*\|\*\d\+\$\)\(\.\(\d*\|\*\|\*\d\+\$\)\)\=\([hlL]\|ll\)\=\([bdiuoxXDOUfeEgGcCsSpn]\|\[\^\=.[^]]*\]\)" contained
+  if !exists("c_no_c99") " ISO C99
+    syn match	cFormat		display "%\(\d\+\$\)\=[-+' #0*]*\(\d*\|\*\|\*\d\+\$\)\(\.\(\d*\|\*\|\*\d\+\$\)\)\=\([hlLjzt]\|ll\|hh\)\=\([aAbdiuoxXDOUfFeEgGcCsSpn]\|\[\^\=.[^]]*\]\)" contained
+  else
+    syn match	cFormat		display "%\(\d\+\$\)\=[-+' #0*]*\(\d*\|\*\|\*\d\+\$\)\(\.\(\d*\|\*\|\*\d\+\$\)\)\=\([hlL]\|ll\)\=\([bdiuoxXDOUfeEgGcCsSpn]\|\[\^\=.[^]]*\]\)" contained
+  endif
   syn match	cFormat		display "%%" contained
   syn region	cString		start=+L\="+ skip=+\\\\\|\\"+ end=+"+ contains=cSpecial,cFormat,@Spell
   " cCppString: same as cString, but ends at end of line