diff --git a/src/ruby/lib/grpc/grpc.rb b/src/ruby/lib/grpc/grpc.rb
index 5f0c42ca2c61d3996f14b06cf320714757dece9f..f46710dc74226acc3024be8923fce82ce9f3fb7f 100644
--- a/src/ruby/lib/grpc/grpc.rb
+++ b/src/ruby/lib/grpc/grpc.rb
@@ -28,7 +28,7 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 begin
-  ruby_version_dirname = /(\d+\.\d+)/.match(RUBY_VERSION)
+  ruby_version_dirname = /(\d+\.\d+)/.match(RUBY_VERSION).to_s
   distrib_lib_dir = File.expand_path(ruby_version_dirname,
                                      File.dirname(__FILE__))
   if File.directory?(distrib_lib_dir)