Pharmacoeconomics and outcomes research (PEOR) demonstrates the added value of health services and treatments and is used by a variety of individuals in numerous settings to optimize patient care. Currently, 51 PEOR fellowship programs are publicized on Web sites from organizations such as the American College of Clinical Pharmacy (ACCP), the International Society of Pharmacoeconomics and Outcomes Research (ISPOR), and the Academy of Managed Care Pharmacy. These programs demonstrate the diversity of PEOR fellowships, as they are offered by sponsors in a variety of environments (e.g., academia, industry, consulting services, United States managed care, and government). Although the program sponsors vary, all fellowships should have the common goal of providing directed, highly individualized postgraduate training designed to prepare participants to become independent PEOR researchers. Like any health discipline, advancements in knowledge and technology along with changes in health care systems require refinement of existing training programs, including PEOR fellowships. Members of ACCP and ISPOR developed a survey instrument to assess structure, educational objectives, and outcome measures of PEOR fellowship programs. The survey objectives were to determine PEOR researchers' beliefs regarding qualifications of the training site, program, and preceptors(s) as well as fellowship applicant requirements, research commitment, didactic coursework and evaluation of fellows' research skills; and to develop PEOR fellowship guidelines based on data obtained from the survey. Pharmacoeconomics and outcomes research fellowship guidelines were originally published in 1999; this document outlines the revised PEOR fellowship guidelines based on recent literature and results of the ACCP-ISPOR survey described above. These guidelines are intended to assist PEOR researchers design, refine, and self-assess their fellowship program and to serve as a tool for prospective PEOR fellowship candidates to evaluate programs.