This volume is intended for SPI (software process improvement) managers and researchers, quality managers, and experienced project and research managers. The papers constitute the research proceedings of the 12th EuroSPI (European Software Process Improvement, www.eurospi.net) conference held in Budapest, 9-11 November 2005, Hungary. Conferences have been held in 1994 in Dublin, 1995 in Vienna (Austria), 1997 in Budapest (Hungary), 1998 in Gothenburg (Sweden), 1999 in Pori(Finland), 2000 in Copenhagen(Denmark), 2001 in L- erick (Ireland), 2002 in Nuremberg (Germany), 2003 in Graz (Austria), and 2004 in Trondheim (Norway). EuroSPI established an experience library (- brary.eurospi.net) which will be continuously extended over the next years and will be made available to all attendees. EuroSPI also created an umbrella init- tive for establishing a European Quali?cation Network in which di?erent SPINs and national initiatives join mutually bene?cial collaborations. From 2005, through EuroSPI partners and networks, in collaboration with the European Union (supported by the EU Leonardo da Vinci Programme), a certi?cation body will be created for the IT and services sector so as to o?er SPI knowledge and certi?cates to industry, establishing close knowledge transfer links between research and industry. The biggest value of EuroSPI lies in its function as a European knowledgeand experience exchangemechanism between SPI research institutions and industry.