Perceptions of the certification standards of the American Board of Internal Medicine (ABIM) and the qualities of care provided by certified and non-certified practicing internists are reported from surveys of ABIM Board members, internal medicine program directors, and samples of third-year residents, practicing internists, nurses, and hospital administrators. ABIM pass rates were estimated accurately and viewed as appropriate. Physicians perceived the deficiencies of non-certifiable residents to be in clinical judgment and factual knowledge; non-physicians indicated deficiencies in humanistic qualities. The groups estimated that approximately 70% of all practicing internists and 37% of the non-certified internists they know provide excellent care while 15% of the certified internists give inappropriate care. Perceived deficiencies of internists giving low-quality care were nearly identical to those of non-certifiable residents. The results support ABIM's initial certification process and suggest that a written examination with well chosen standards would be useful for experienced internists.