Service-oriented architecture (SOA) has gained significant attention as a means of developing flexible and modular systems. Academic studies of SOA as a systems development philosophy abound, and recent industry surveys indicate that most firms are also actively pursuing SOA initiatives. This article uses a rigorous case-study methodology to examine five main benefits of SOA – business flow transparency, plug-and-play capability, leveraging legacy systems, rapid product development time, and reduced costs – as perceived by the organizations that have implemented SOA. Participants in this study report that not all stated benefits are realised due to, among other things, a failure of service-oriented thinking at an organisational level, problems allocating financial responsibility for services within and between organisations, and a lack of mature tool chains. These issues are significant because they are, according to the participants in the study, critical to leveraging investments in SOA.