diff --git a/sdformat.spec b/sdformat.spec
index 26180db..af392e5 100644
--- a/sdformat.spec
+++ b/sdformat.spec
@@ -21,6 +21,8 @@ BuildRequires:	graphviz
 BuildRequires:	gtest-devel
 BuildRequires:  ignition-math-devel
 BuildRequires:  ruby >= 1.9
+BuildRequires:  /usr/bin/ruby
+BuildRequires:  rubygem-multi_xml
 BuildRequires:	texlive-refman
 BuildRequires:	tinyxml-devel
 BuildRequires:	urdfdom-devel