rubinius/rubinius

diff --git a/mspec/lib/mspec/commands/mspec.rb b/mspec/lib/mspec/commands/mspec.rb
index 6770dce..87d6bbf 100644
--- a/mspec/lib/mspec/commands/mspec.rb
+++ b/mspec/lib/mspec/commands/mspec.rb
@@ -39,7 +39,7 @@ class MSpecMain < MSpecScript
       config[:flags] << '--gdb'
     end
     options.on("-A", "--valgrind", "Run under valgrind") do
-      config[:flags] << '--valgrind'
+      config[:valgrind] = true
     end
     options.on("--warnings", "Don't supress warnings") do
       config[:flags] << '-w'
@@ -149,6 +149,9 @@ class MSpecMain < MSpecScript
 
     if config[:multi] and config[:command] == "ci"
       multi_exec argv
+    elsif config[:valgrind]
+      argv.unshift config[:target]
+      exec 'valgrind', *argv
     else
       exec config[:target], *argv
     end