diff --git a/engine/common/common.h b/engine/common/common.h
index f96eda0d..b60dcf34 100644
--- a/engine/common/common.h
+++ b/engine/common/common.h
@@ -699,7 +699,7 @@ void Host_WriteConfig( void );
 qboolean Host_IsLocalGame( void );
 qboolean Host_IsLocalClient( void );
 void Host_ShutdownServer( void );
-void Host_Error( const char *error, ... ) _format( 1 );
+void Host_Error( const char *error, ... ) _format( 1 ) NORETURN;
 void Host_PrintEngineFeatures( void );
 void Host_Frame( float time );
 void Host_InitDecals( void );
diff --git a/engine/common/system.h b/engine/common/system.h
index 9656dbca..48fb1807 100644
--- a/engine/common/system.h
+++ b/engine/common/system.h
@@ -51,7 +51,7 @@ char *Sys_GetClipboardData( void );
 const char *Sys_GetCurrentUser( void );
 int Sys_CheckParm( const char *parm );
 void Sys_Warn( const char *format, ... ) _format( 1 );
-void Sys_Error( const char *error, ... ) _format( 1 );
+void Sys_Error( const char *error, ... ) _format( 1 ) NORETURN;
 qboolean Sys_LoadLibrary( dll_info_t *dll );
 void* Sys_GetProcAddress( dll_info_t *dll, const char* name );
 qboolean Sys_FreeLibrary( dll_info_t *dll );