Too often the professional development provided for teachers of mathematics is a short-term, one-shot effort. Today's shrinking budgets, increasing class sizes, and growing demands on teachers' time present further challenges. For the past six years, staff development efforts in the author's district have focused on language arts with little comprehensive work being done to support mathematics. Five years ago, before the current economic decline, personnel at the district level and in the teachers' union worked collaboratively to create a system of ongoing staff development for teachers in all subject areas. This article describes the teaching and learning cooperative (TLC) which provides avenues for teachers to initiate and design professional learning to fit their needs. The TLC program was designed to improve student learning by supporting professional development that closely relates to and supports the work of teaching and the process of learning. Teachers may propose their own TLC professional development options. The proposals must support the strategic vision of the district to provide college readiness for all students and must align with the state content standards, the district teaching standards, and the National Staff Development Council standards for adult learners. "Resources for TLCs" is appended. (Contains 1 table.)