A description is given of a client-based approach to staff development that emphasizes ongoing professional growth and learning for teachers. The underlying assumptions of the program are that teachers possess important clinical expertise, and that professional learning is an adaptive, heuristic process that is long-term and nonlinear. The program is tied to school-site program building efforts since professional learning is critically influenced by organizational factors in the school site and district. The model for this approach to staff development provides for: (1) an extensive, thorough diagnosis of present instructional problems in the school setting; (2) a careful selection from among alternative methods and materials; (3) extensive teacher involvement, from early planning and diagnostic stages to final implementation; (4) open, direct channels for communication between all participants; and (5) a flexible time-line for implementation. A description is given of how the client-based model of staff development was implemented recently in the design and delivery of a reading inservice program for elementary teachers in a medium-sized Florida city. This professional development model gives priority to improving teachers' decision making skills and enhancing their professional autonomy. It also enables teachers, administrators, parents, and university consultants to become active partners in the school improvement process. (JD)