This book constitutes the throughly refereed post-proceedings of the Second International Workshop on Global Optimization and Constraint Satisfaction, COCOS 2003, held in Lausanne, Switzerland in Nowember 2003. The 13 revised full papers presented were carefully selected and went through two rounds of reviewing and improvement. The papers are devoted to theoretical, algorithmic, and application-oriented issues in global constrained optimization and constraint satisfaction; they are organized in topical sections on constraint satisfaction problems, global optimization, and applications.