The three-year New York City Mathematics Project is a staff development effort for mathematics teachers grades K through 12, modeled on the National Writing Project. The teachers will come from six districts in the Bronx. Through after school courses, summer institutes, leadership seminars, on-site consulting, and the development of a mathematics resource center, a cadre of mathematics teacher leaders will be established. A total of ninety teachers will be involved in the project; 30 of these will be part of the project for three years; 15 will be in the project for two full years; the remained all will be with the project for at least a year. A four-stage model of teacher development which supports gradual implementation of new ideas and movement toward leadership, guides the project. Teachers in Stage Four will be involved in leadership activities within their own schools and locally. Mathematics content focus includes geometry, probability, and number theory. A series of "urban vignettes" that can be used as an inservice tools for professional development of urban mathematics teachers will be produced and published through the project. Cost sharing is provided by the university and NYC school districts as 60% of the NSF award.