The reemergence of the professional development school movement in North America may mark the beginning of a paradigm shift in clinical teacher education. Conceptual and structural obstacles to student teacher learning in practicums that must be addressed if the professional development school is to achieve its goals are discussed. The conceptual barriers result from inadequate conceptions of reflection that neglect teachers' practical theories, values, the social conditions of schooling, and the social aspects of reflection. The structural barriers include the placement of student teachers in single classrooms rather than schools, the selection of placements, supervisory relations, and the lack of multicultural placements. Professional development schools offer an opportunity to overcome these obstacles by altering the power and role relationships in the practicum.