There's a new binary serializer available for WP7 - SharpSerializer. It 's OSS and is currently hosted on CodePlex . Available via NuGet as well. I received an anonymous comment the other day on a blog post about serialisation performance on WP7. So I thought I would re-run the test app and see how it compared, the original post can be found here . My first attempt failed because the NuGet packages were invalid, so after the author had corrected this I decided to run the test again. This time though I got the latest code and explicitly compiled this as a WP7 class library. So I ran the same test, binary serialize a collection containing 1000 items and display the performance results to the output window in visual studio: The results don't lie, sharpSerializer is good, but SilverlightSerializer still has it for me. Good to see some competition in this space I'll be keeping an eye on this project.