diff --git a/code/sys/sys_unix.c b/code/sys/sys_unix.c
index 0cffd4f1..60050931 100644
--- a/code/sys/sys_unix.c
+++ b/code/sys/sys_unix.c
@@ -123,6 +123,8 @@ qboolean Sys_RandomBytes( byte *string, int len )
 	if( !fp )
 		return qfalse;
 
+	setvbuf( fp, NULL, _IONBF, 0 ); // don't buffer reads from /dev/urandom
+
 	if( fread( string, sizeof( byte ), len, fp ) != len )
 	{
 		fclose( fp );