Index: apps/app_voicemail.c
===================================================================
--- apps/app_voicemail.c	(revision 143399)
+++ apps/app_voicemail.c	(working copy)
@@ -2926,8 +2926,8 @@
 	pbx_builtin_setvar_helper(ast, "VM_CONTEXT", context);
 	pbx_builtin_setvar_helper(ast, "VM_MAILBOX", mailbox);
 	pbx_builtin_setvar_helper(ast, "VM_CALLERID", ast_callerid_merge(callerid, sizeof(callerid), cidname, cidnum, "Unknown Caller"));
-	pbx_builtin_setvar_helper(ast, "VM_CIDNAME", (cidname ? cidname : "an unknown caller"));
-	pbx_builtin_setvar_helper(ast, "VM_CIDNUM", (cidnum ? cidnum : "an unknown caller"));
+	pbx_builtin_setvar_helper(ast, "VM_CIDNAME", (!ast_strlen_zero(cidname) ? cidname : "an unknown caller"));
+	pbx_builtin_setvar_helper(ast, "VM_CIDNUM", (!ast_strlen_zero(cidnum) ? cidnum : "an unknown caller"));
 	pbx_builtin_setvar_helper(ast, "VM_DATE", date);
 	pbx_builtin_setvar_helper(ast, "VM_CATEGORY", category ? ast_strdupa(category) : "no category");
 }