Health care in the 21^st century is characterized by a managed-care environment in which medical providers rely on technology to enhance their practice, not only in terms of better care, but also to improve efficiency. A perceived attenuation of medical professionalism, attributed to economic forces, technological advances, and the resulting changes in the social contract between medical providers and their patients has stimulated renewed interest in promoting professionalism as a critical competency in the field of medicine. A review of the literature has shown that educators, professional organizations, accrediting bodies, and independent agencies worldwide are making efforts to identify and assess the behaviors of medical professionalism as a means of ensuring an adequate supply of competent, caring individuals to provide for the health care needs of the population. The purpose of this study was to gain consensus among physician assistant educators about the desired behaviors of professionalism in physician assistant students. A modified Delphi technique was used in the study to elicit input from a group of geographically dispersed physician assistant educators. Based on the literature review, eight themes were used to categorize the behaviors of professionalism: integrity, respect, personal demeanor & appearance, accountability, commitment to excellence, empathy, team player qualities, and self-reflection. Fifty-one behaviors representing professionalism among physician assistant students were identified by the panel of experts as being moderately important to essential. PA educators are responsible for socializing their students to the shared values, goals and behaviors of the profession, and the educational setting has the power to influence the development of appropriate lifelong skills that define professionalism. Professionalism skills developed during education and training provide the basis for professional behavior in clinical practice. As such, identifying the behaviors of professionalism is an appropriate initial step towards helping PA programs prepare students to become successful and effective clinical practitioners. This study lays the groundwork for further development of this important component of the physician assistant student learning experience.