Geometric Modeling and Processing (GMP) is a biennial international conference on geometric modeling, simulation and computing, which provides researchers and practitioners with a forum for exchanging new ideas, discussing new app- cations, and presenting new solutions. Previous GMP conferences were held in Pittsburgh (2006), Beijing (2004), Tokyo (2002), and Hong Kong (2000). This, the 5th GMP conference, was held in Hangzhou, one of the most beautiful cities in China. GMP 2008 received 113 paper submissions, covering a wide spectrum of - ometric modeling and processing, such as curves and surfaces, digital geometry processing, geometric feature modeling and recognition, geometric constraint solving, geometric optimization, multiresolution modeling, and applications in computer vision, image processing, scientific visualization, robotics and reverse engineering. Each paper was reviewed by at least three members of the program committee andexternalreviewers.Basedonthe recommendations of the revi- ers, 34 regular papers were selected for oral presentation, and 17 short papers were selected for poster presentation. All selected papers are included in these proceedings. We thank all authors, external reviewers and program committee members for their great effort and contributions, which made this conference a success.