diff --git a/openswan.spec b/openswan.spec
index 518900e..97d1b4f 100644
--- a/openswan.spec
+++ b/openswan.spec
@@ -11,6 +11,7 @@ Source2:	openswan.service
 Patch0:		openswan-2.6.28-manfix.patch
 BuildRequires:	bison
 BuildRequires:	docbook-dtd412-xml
+BuildRequires:	docbook-style-xsl
 BuildRequires:	dos2unix
 BuildRequires:	flex
 BuildRequires:	xmlto