This book constitutes the thoroughly refereed post-proceedings of the Second International Conference on the Quality of Software Architectures, QoSA 2006, held in V?ster?s, Sweden in June 2006, co-located with the 9th International Symposium on Component-Based Software Engineering, CBSE 2006.

The 12 revised full papers presented together with the abstracts of 2 keynote talks and 3 tutorials were carefully reviewed and selected from 30 submissions. The papers are organized in topical sections on architecture evaluation: selecting alternatives, managing and applying architectural knowledge, architectural evaluation: performance prediction, processes for supporting architecture quality, models for architecture evaluation, and architectural evaluation.