In this paper, we present two descriptive case studies covering the re-engineering and further evolution of adopting service oriented architecture (SOA) in industry. The first case was carried out for a company in the transport sector with an application portfolio of over 700 systems. The second case study was conducted for an organization in the public sector. The goal of both case studies is to identify possible benefits and drawbacks of realizing SOA in large organizations in order to obtain a better perspective on the real, rather than the assumed, benefits of SOA in practice. We describe how the two cases were developed and carried out, and discuss the experiences gained and lessons learned from adopting SOA in the two organizations. Based on these findings, we propose several directions for further research. Accepted for publication in the Journal of Software Maintenance and Evolution: Research and Practice, 2011, Wiley-Blackwell