diff --git a/antlr.spec b/antlr.spec
index 9a2b280..b54ab17 100644
--- a/antlr.spec
+++ b/antlr.spec
@@ -60,8 +60,12 @@ BuildRequires:  %{_bindir}/gcj, %{__make}
 BuildArch:      noarch
 %endif
 BuildRequires:  ant
+
+%ifnarch s390 s390x ppc64
 BuildRequires:  mono-core
 BuildRequires:  mono-winforms
+%endif
+
 BuildRequires:  %{__perl}, java-javadoc
 Requires:       jpackage-utils
 Requires(post): %{_sbindir}/update-alternatives