MSN 2005, the First International Conference on Mobile Ad-hoc and Sensor Networks, was held during 13-15 December 2005, in Wuhan, China. The conference provided a forum for researchers and practitioners to exchange research results and share development experiences. MSN 2005 attracted 512 submissions (including the submissions to the Modeling and Security in Next Generation Mobile Information Systems (MSNG) workshop), among which 100 papers were accepted for the conf- ence and 12 papers were accepted for the workshop. We would like to thank the International Program Committee for their valuable time and effort in reviewing the papers. Special thanks go to the conference PC Vi- chairs, Ivan Stojmenovic, Jang-Ping Sheu and Jianzhong Li for their help in ass- bling the International PC and coordinating the review process. We would also like to thank the Workshop Chair, Dongchun Lee, for organizing the workshop. We would like to express our gratitude to the invited speakers, Laxmi Bhuya, Lionel Ni and Taieb Znati, for their insightful speeches. Finally, we would like to thank the Local Organization Chair, Chuanhe Huang, for making all the local - rangements for the conference. December 2005 Xiaohua Jia Jie Wu Yanxiang He Organization Steering Co-chairs Lionel Ni, Hong Kong University of Science and Technology, HKSAR Jinnan Liu, Wuhan University, PRC General Co-chairs Taieb Znati, University of Pittsburgh, USA Yanxiang He, Wuhan University, PRC Program Co-chairs Jie Wu, Florida Atlantic University, USA Xiaohua Jia, City University of Hong Kong, HKSAR Program Vice Chairs