diff --git a/htdig/htdig.spec b/htdig/htdig.spec
index 0f68cc9181..b0b09a4bcf 100644
--- a/htdig/htdig.spec
+++ b/htdig/htdig.spec
@@ -40,7 +40,7 @@ Source0:      http://ftp.sourceforge.net/htdig/htdig-%{version}.tar.gz
 #   build information
 Prefix:       %{l_prefix}
 BuildRoot:    %{l_buildroot}
-BuildPreReq:  OpenPKG, openpkg >= 0.9-20011025.0, make, flex
+BuildPreReq:  OpenPKG, openpkg >= 0.9-20011025.0, make, flex, zlib
 PreReq:       OpenPKG, openpkg >= 0.9-20011025.0
 AutoReq:      no
 AutoReqProv:  no