This book constitutes the refereed proceedings of the 22nd IFIP WG 6.1 International Conference on Testing Software and Systems, ICTSS 2010, held in Natal, Brazil, in November 2010. ICTSS 2010 is the merger of the 22nd IFIP International Conference on Testing of Communicating Systems (TESTCOM) and the 10th International Workshop on Formal Approaches to Testing of Software (FATES). The 16 revised full papers presented together with 2 invited presentations were carefully selected from 60 submissions. The papers cover a wide range of topics in the field of testing of general software and systems such as test automation, integration testing, test case selection, search based testing, combinatorial testing, inductive testing, test architectures for large-scale systems, and end-to-end performance testing.