Medical school faculty members are being asked to assume new academic duties for which they have received no formal training. These include time-efficient ambulatory care teaching, case-based tutorials, and new computer-based instructional programs. In order to succeed at these new teaching tasks, faculty development is essential. It is a tool for improving the educational vitality of academic institutions through attention to the competencies needed by individual teachers, and to the institutional policies required to promote academic excellence. Over the past three decades, strategies to improve teaching have been influenced by the prevailing theories of learning and research on instruction, which are described. Research on these strategies suggests that workshops and students' ratings of instruction, coupled with consultation and intensive fellowships, are effective strategies for changing teachers' actions. A comprehensive faculty development program should be built upon (1) professional development (new faculty members should be oriented to the university and to their various faculty roles); (2) instructional development (all faculty members should have access to teaching-improvement workshops, peer coaching, mentoring, and/or consultations); (3) leadership development (academic programs depend upon effective leaders and well-designed curricula; these leaders should develop the skills of scholarship to effectively evaluate and advance medical education); (4) organizational development (empowering faculty members to excel in their roles as educators requires organizational policies and procedures that encourage and reward teaching and continual learning). Comprehensive faculty development, which is more important today than ever before, empowers faculty members to excel as educators and to create vibrant academic communities that value teaching and learning.