diff --git a/src/butc/error_macros.h b/src/butc/error_macros.h
index 5f6c760caf..132afa1936 100644
--- a/src/butc/error_macros.h
+++ b/src/butc/error_macros.h
@@ -26,11 +26,15 @@
         }
 
 extern void ErrorLog(int debug, afs_int32 task, afs_int32 error1,
-		     afs_int32 error2, char *fmt, ...);
-extern void TapeLog(int debug, afs_int32 task, afs_int32 error1,
-		    afs_int32 error2, char *fmt, ...);
-extern void TLog(afs_int32 task, char *fmt, ...);
+		     afs_int32 error2, char *fmt, ...)
+	AFS_ATTRIBUTE_FORMAT(__printf__, 5, 6);
 
+extern void TapeLog(int debug, afs_int32 task, afs_int32 error1,
+		    afs_int32 error2, char *fmt, ...)
+	AFS_ATTRIBUTE_FORMAT(__printf__, 5, 6);
+
+extern void TLog(afs_int32 task, char *fmt, ...)
+	AFS_ATTRIBUTE_FORMAT(__printf__, 2, 3);
 
 extern void FreeNode(afs_int32 taskID);
 extern void CreateNode(struct dumpNode **newNode);
diff --git a/src/butc/lwps.c b/src/butc/lwps.c
index 3f4017ffc1..0f1daf6d4c 100644
--- a/src/butc/lwps.c
+++ b/src/butc/lwps.c
@@ -299,7 +299,7 @@ ELog(afs_int32 task, char *fmt, ...)
     va_end(ap);
 
     /* Sends message to ErrorLog, TapeLog and stdout */
-    ErrorLog(0, task, 0, 0, tmp);
+    ErrorLog(0, task, 0, 0, "%s", tmp);
 }
 
 /* first proc called by anybody who intends to use the device */
diff --git a/src/kauth/kaserver.h b/src/kauth/kaserver.h
index f4c8037562..ce77443231 100644
--- a/src/kauth/kaserver.h
+++ b/src/kauth/kaserver.h
@@ -167,5 +167,7 @@ extern int kaux_islocked(afs_int32 to, u_int attempts, u_int locktime);
 
 extern afs_int32 krb4_cross;
 
-extern afs_int32 es_Report(char *fmt, ...);
+extern afs_int32 es_Report(char *fmt, ...)
+    AFS_ATTRIBUTE_FORMAT(__printf__, 1, 2);
+
 #define LOCKPW
diff --git a/src/lwp/test/seltest.h b/src/lwp/test/seltest.h
index 09d538fa52..f29c3e55db 100644
--- a/src/lwp/test/seltest.h
+++ b/src/lwp/test/seltest.h
@@ -35,7 +35,10 @@ typedef struct {
 void OpenFDs(int);
 void assertNullFDSet(int fd, fd_set *);
 void Die(int flag, char *);
-void Log(char *fmt, ...);
+
+void Log(char *fmt, ...)
+    AFS_ATTRIBUTE_FORMAT(__printf__, 1, 2);
+
 void sendOOB(int);
 void recvOOB(int);
 
diff --git a/src/sys/sys_prototypes.h b/src/sys/sys_prototypes.h
index 8ce924562a..5ddcc476bd 100644
--- a/src/sys/sys_prototypes.h
+++ b/src/sys/sys_prototypes.h
@@ -36,7 +36,9 @@ extern void inparam_conversion(afs_int32, char *, afs_int32);
 extern void outparam_conversion(afs_int32, char *, afs_int32);
 
 /* rmtsyss.c */
-extern void rmt_Quit(char *msg, ...);
+extern void rmt_Quit(char *msg, ...)
+    AFS_ATTRIBUTE_FORMAT(__printf__, 1, 2);
+
 extern void rmtsysd(void);
 
 /* setpag.c */
diff --git a/src/ubik/ubik.p.h b/src/ubik/ubik.p.h
index 315a80f461..adcbdac865 100644
--- a/src/ubik/ubik.p.h
+++ b/src/ubik/ubik.p.h
@@ -395,7 +395,8 @@ extern afs_int32 ContactQuorum_DISK_SetVersion(struct ubik_trans *atrans,
 					       ubik_version *OldVersion,
 					       ubik_version *NewVersion);
                                               
-extern void panic(char *format, ...); 
+extern void panic(char *format, ...)
+    AFS_ATTRIBUTE_FORMAT(__printf__, 1, 2);
 
 extern afs_uint32 ubikGetPrimaryInterfaceAddr(afs_uint32 addr); 
 /*\}*/
@@ -437,10 +438,17 @@ extern void ulock_Debug(struct ubik_debug *aparm);
 extern int uvote_ShouldIRun(void);
 extern afs_int32 uvote_GetSyncSite(void);
 extern int uvote_Init(void);
-extern void ubik_vprint(const char *format, va_list ap);
-extern void ubik_print(const char *format, ...);
-extern void ubik_dprint(const char *format, ...);
-extern void ubik_dprint_25(const char *format, ...);
+extern void ubik_vprint(const char *format, va_list ap)
+    AFS_ATTRIBUTE_FORMAT(__printf__, 1, 0);
+
+extern void ubik_print(const char *format, ...)
+    AFS_ATTRIBUTE_FORMAT(__printf__, 1, 2);
+
+extern void ubik_dprint(const char *format, ...)
+    AFS_ATTRIBUTE_FORMAT(__printf__, 1, 2);
+
+extern void ubik_dprint_25(const char *format, ...)
+    AFS_ATTRIBUTE_FORMAT(__printf__, 1, 2);
 /*\}*/
 
 #endif /* UBIK_INTERNALS */