This book constitutes the refereed proceedings of the 13th International SPIN workshop on Model Checking Software, SPIN 2006, held in Vienna, Austria in March/April 2006 as satellite event of ETAPS 2006.

The 16 revised full papers presented together with 3 tool presentation papers were carefully reviewed and selected from 44 submissions. The papers are organized in topical sections on directed model checking, markovian systems, distributed model checking, advanced handling of data aspects, applications, assume – guarantee, partial order reduction, tool demonstrations.