The First ICST International Workshop on Security in Emerging Wireless Communication and Networking Systems (SEWCN 2009) was held in Athens, Greece, on September 14, in conjunction with SecureComm 2009. SEWCN 2009 was sponsored by the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering (ICST). The workshop chairs were Qijun Gu from Texas State University-San Marcos, USA, and Wanyu Zang from Western Illinois University, USA. The workshop invited 20 researchers from academia and industry around the world in the areas of networking and security to form the Program Committee. The workshop received nine submissions, and each submission received two or three double-blind reviews. The review process started on July 6 and ended on July 27. In all, 21 reviews were received. Based on the review scores and comments, seven papers with an average score of 0 or better were accepted.