California's health care industry includes workers prepared in many ways to perform many jobs. One significant group of health care workers prepared to provide care that often overlaps with physician-generated services is known as "nonphysician providers." Commonly, this label refers to nurse practitioners (NPs), certified nurse midwives (CNMs), and physician assistants (PAs). In this article, we will describe this group in five main areas: (1) the characteristics of the current and projected workforce and programs preparing these professionals; (2) the current skill expectations and knowledge bases of each; (3) trends in the education of these health professionals; (4) innovative models of education of these health professionals; and (5) the inclusion of NPs, PAs, and CNMs in workforce planning in a changing health care system. We conclude that, particularly in light of the overlapping functions of this provider group with many physician functions, the NP, CNM, and NP workforces must be recognized and considered when planning for the future of the physician workforce.