Theseproceedingscontainthepapersofthe3rdEuropeanWorkshoponSecurity and Privacy in Ad Hoc and Sensor Networks (ESAS 2006), which was held in Hamburg, Germany, September 20 21, 2006, in conjunction with the 11th European Symposium on Research in Computer Security (ESORICS 2006). This year, a total of 44 full papers were submitted to ESAS. Each subm- ted paper was reviewed by at least three expert referees. After a short period of discussion and deliberation, the Program Committee selected 14 papers for presentation and subsequent publication in the workshop proceedings. This c- responds to an...