Organizational theory suggests great pessimism about the potential of school districts for supporting educational improvement. The traditional view is that educational organizations--and school districts, in particular--are loosely coupled organizations where the main resources for central leadership are insufficient to penetrate the isolation of the classroom (Bidwell, 1965; Weick, 1976). The great variation in how mid-level district bureaucrats interpret the same policy (Spillane, 1998) and the apparent vulnerability of top district leadership to various forms of political intervention, resulting in frequent turnover in that position (Brunner & Bjork, 2001), both weaken districts' potential for concerted action. Yet dissenters argue that districts have considerable resources to influence instruction and that if districts seem to lack influence, it may be because they fail to take advantage of the resources at their disposal (Corwin & Borman, 1988; Floden, Porter, Alford, Freeman, Susan, Schmidt, et al., 1988). More recently, analysts have asserted that districts can play a key role in supporting instructional reform (Hightower, Knapp, Marsh, & McLaughlin, 2002; Spillane, 1996). Resulting from an applied project to help districts better track their professional development activities, this paper contributes to the second view through an analysis of three urban school districts in New Jersey. A comparison of these districts suggests that districts in relatively similar demographic and policy contexts take very different approaches to offering professional development. In examining this pathway to improved teaching, and presumably improved student learning, this paper provides an overview of research on professional development as a tool for reform and districts' role in providing it. After describing the study's policy context and methodology and the authors' relationship to the districts, three major topics are discussed: an analysis of district leadership and its vision for professional development, presentation of the formal programs for professional development and their perceptions by teachers, and a depiction of how teachers say the district professional development programs influence their own practice.