diff --git a/Source/mpqapi.h b/Source/mpqapi.h
index 7f4fe1498..703013fe4 100644
--- a/Source/mpqapi.h
+++ b/Source/mpqapi.h
@@ -12,7 +12,7 @@
 namespace devilution {
 
 struct _FILEHEADER {
-	int signature;
+	uint32_t signature;
 	int headersize;
 	uint32_t filesize;
 	uint16_t version;