diff --git a/include/types/proto_http.h b/include/types/proto_http.h
index 935be8ce6..0c1f50f9b 100644
--- a/include/types/proto_http.h
+++ b/include/types/proto_http.h
@@ -29,6 +29,7 @@
 
 #include <types/hdr_idx.h>
 #include <types/filters.h>
+#include <types/sample.h>
 
 /* These are the flags that are found in txn->flags */