diff --git a/rubygem-crack.spec b/rubygem-crack.spec
index ad9c558..7f410bb 100644
--- a/rubygem-crack.spec
+++ b/rubygem-crack.spec
@@ -3,12 +3,16 @@
 Summary: Really simple JSON and XML parsing, ripped from Merb and Rails
 Name: rubygem-%{gem_name}
 Version: 0.4.2
-Release: 3%{?dist}
+Release: 4%{?dist}
 Group: Development/Languages
 License: MIT
 URL: http://github.com/jnunemaker/crack
 Source0: http://rubygems.org/gems/%{gem_name}-%{version}.gem
+# ruby package has just soft dependency on rubygem(bigdecimal), while
+# crack always requires it.
+Requires: rubygem(bigdecimal)
 BuildRequires: rubygems-devel
+BuildRequires: rubygem(bigdecimal)
 BuildRequires: rubygem(minitest)
 BuildRequires: rubygem(safe_yaml)
 BuildArch: noarch
@@ -65,6 +69,9 @@ popd
 %{gem_instdir}/test
 
 %changelog
+* Mon Apr 11 2016 Vít Ondruch <vondruch@redhat.com> - 1:0.4.2-4
+- Explicitly set rubygem(bigdecimal) dependency.
+
 * Thu Feb 04 2016 Fedora Release Engineering <releng@fedoraproject.org> - 1:0.4.2-3
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_24_Mass_Rebuild