In 1991, the Newark School District (New Jersey), through the partnership of the Newark Teachers' Union and Montclair State University, established the first professional development school (PDS) in the city. Used primarily as a center for retooling elementary grade teachers in grades 6, 7, and 8, the school has come to play a pivotal role in the school district's reshaping of current staff development programs. Since 1991, 205 teachers have participated in PDS training. This report presents the results from the first formal evaluation of the program. In general, findings suggest the promising potential of the PDS model through its impact on teacher attitudes and behaviors as well as student performance. However, the degree of success of the PDS is significantly attenuated by several problems: (1) the fragmentation of policies as they relate to wider attempts to introduce change within the school system; (2) an insufficiency in the diversity and flexibility of the model to accommodate the different needs of teachers and schools; and (3) a follow-up plan that is not sufficiently thorough to confront the problems teachers encounter once they return to their home schools. At present, these problems hinder the ability of the PDS model to generate fundamental and sustaining changes in the caliber of the district's teaching force. An appendix contains scales and subscales from the PDS teacher surveys. (Contains 10 tables, 3 figures, and 26 references.) (Author/SLD)