diff --git a/source/pr_load.c b/source/pr_load.c
index 20872f0..77d3e46 100644
--- a/source/pr_load.c
+++ b/source/pr_load.c
@@ -123,6 +123,9 @@ static void PR_LoadDef(ddef_t *def, byte const **data)
 	def->type   = ReadLittleShort(data);
 	def->ofs    = ReadLittleShort(data);
 	def->s_name = ReadLittleLong(data);
+
+	if(def->ofs % 4 != 0)
+		Host_Error("PR_LoadDef: offset must be 4 byte aligned");
 }
 
 static void PR_LoadGlobalDefs(byte const *data)