This book contains the proceedings of a third workshop on the theme of Software Arc- tecture for Product Families. The first two workshops were organised by the ESPRIT project ARES, and were called “Development and Evolution of Software Architectures for Product Families”. Proceedings of the first workshop, held in November 1996, were only published electronically at: “http: //www.dit.upm.es/ ares/”. Proceedings of the second workshop, held in February 1998, were published as Springer LNCS 1429. The ARES project was finished in February 1999. Several partners continued – operation in a larger consortium, ITEA project 99005, ESAPS. As such it is part of the European Eureka ! 2023 programme. The third workshop was organised as part of the ESAPS project. In order to make the theme of the workshop more generic we decided to rename it “International Workshop on Software Architectures for Product Families”. As with the earlier two workshops we managed to bring together people working in the so- ware architecture of product families and in software product-line engineering. Submitted papers were grouped in five sessions. Moreover, we introduced two s- sions, one on configuration management and one on evolution, because we felt that d- cussion was needed on these topics, but there were no submitted papers for these subjects. Finally, we introduced a surveys session, giving an overview of the present situation in Europe, focussed on ESAPS, and in the USA, focussed on the SEI Product Line Systems Program.