This book constitutes the refereed proceedings of the 10th International Symposium, PETS 2010, held in Berlin, Germany in July 2010. The 16 revised full papers were carefully reviewed and selected from 57 submissions for inclusion in the book. The papers handle topics such as access control, privacy of web based search, anonymus webs of trust, security attacks, active timing attacks in lo-latency anonymus communication, network topology and web search with malicious adversaries