The goal of software engineering is to achieve high-quality software in a cost-effective, timely, and reproducible manner. Advances in technology offer reductions in cost and schedule, but their effect on software quality often remains unknown. The International Conferenceon the Quality of Software Architectures(QoSA 2005)focusedon software architectures and their relation to software quality, while the International Workshop on Software Quality (SOQUA 2005) mainly focused on quality assurance and more precisely on software testing. These events complement each other in their view on software quality. One of the main motivations for explicitly modelling software architectures is to enable reasoning on software quality. From a software engineering perspective, a so- ware architecture not only depicts the coarse-grained structure of a program, but also includes additional information such as the program's dynamics (i. e. , the ?ows of c- trol through the system) and the mapping of its components and connections to e- cution environments (such as hardware processors, virtual machines, network conn- tions, and the like). In this area, QoSA 2005is concernedwith researchand experiences that investigate the in?uence a speci?c software architecturehas on software quality - pects. Additionally,the developmentof methodsto evaluate software architectureswith respect to these quality attributes is considered to be an important topic. The quality - tributes of interest include external properties, such as reliability and ef?ciency, as well as internal properties, such as maintainability.