diff --git a/lib/delayed/recurring_job.rb b/lib/delayed/recurring_job.rb
index e87cb9a..2a3756b 100644
--- a/lib/delayed/recurring_job.rb
+++ b/lib/delayed/recurring_job.rb
@@ -84,6 +84,8 @@ def deserialize_duration(serialized)
       case serialized
       when Hash
         ActiveSupport::Duration.new(serialized[:value], serialized[:parts])
+      when /^P/
+        ActiveSupport::Duration.parse(serialized)
       else
         serialized
       end