This volume contains the papers presented at SAT 2010, the 13th International Conference on Theory and Applications of Satis?ability Testing. SAT 2010 was held as part of the 2010 Federated Logic Conference (FLoC) and was hosted by the School of Informatics at the University of Edinburgh, Scotland. In addition to SAT, FLoC included the conferences CAV, CSF, ICLP, IJCAR, ITP, LICS, RTA, as well as over 50 workshops. A?liated with SAT were the workshops LaSh (Logic and Search, co-a?liated with ICLP), LoCoCo (Logics for C- ponent Con?guration), POS (Pragmatics Of SAT), PPC (Propositional Proof Complexity: Theory and Practice), and SMT (Satis?ability Modulo Theories, co-a?liated with CAV). SAT featured three competitions: the MAX-SAT Ev- uation 2010, the Pseudo-Boolean Competition 2010, and the SAT-Race 2010. Many hard combinatorial problems such as problems arising in veri?cation and planning can be naturally expressed within the framework of propositional satis?ability. Due to its wide applicability and enormous progress in the perf- mance of solving methods, satis?ability has become one of today's most imp- tant core technologies. The SAT 2010 call for papers invited the submission of original practical and theoretical research on satis?ability. Topics included but were not limited to proof systems and proof complexity, search algorithms and heuristics, analysis of algorithms, combinatorial theory of satis?ability, random instances vs structured instances, problem encodings, industrial applications, applicationsto combinatorics,solvers,simpli?ers andtools,casestudies and- piricalresults,exactandparameterizedalgorithms.