diff --git a/lib/degem/gemfile.rb b/lib/degem/gemfile.rb
index d0e3267..79fbed0 100644
--- a/lib/degem/gemfile.rb
+++ b/lib/degem/gemfile.rb
@@ -7,7 +7,7 @@ def initialize(dsl)
     end
 
     def rubygems
-      @rubygems ||= gemfile_dependencies + gemspec_dependencies
+      @rubygems ||= (gemfile_dependencies + gemspec_dependencies).uniq
     end
 
     def rails?
diff --git a/test/test_parse_gemfile.rb b/test/test_parse_gemfile.rb
index 1def0f4..1ddccbe 100644
--- a/test/test_parse_gemfile.rb
+++ b/test/test_parse_gemfile.rb
@@ -42,6 +42,7 @@ def test_it_returns_the_parsed_gemfile_including_its_gemspec
         spec.files   = Dir.glob("lib/**/*") + Dir.glob("exe/*")
         spec.authors = ["Riccardo Odone"]
         spec.add_dependency "baz", "~> 1.0"
+        spec.add_development_dependency "foobar", "~> 1.0"
       end
     CONTENT
 
@@ -50,7 +51,7 @@ def test_it_returns_the_parsed_gemfile_including_its_gemspec
         File.write(gemfile_path, "\ngemspec", mode: "a")
         with_file(path: File.join("app", "bar.gemspec"), content: gemspec) do
           actual = Degem::ParseGemfile.new.call(gemfile_path)
-          assert_array %w[foo bar baz], actual.rubygems.map(&:name)
+          assert_array %w[foo bar baz foobar], actual.rubygems.map(&:name)
         end
       end
     end