A statistical interaction model explaining 27 per cent of the variation in physicians' attitudes toward clinical pharmacy among 180 Alabama physicians is presented. Young primary care physicians who prescribe drugs with a low risk of adverse reactions are the most favorable toward pharmacists practicing clinical tasks. Older solo-practice physicians who lack exposure to clinical pharmacy are the least favorable. The implications for the wider acceptance of clinical pharmacy are discussed in terms of its resources of professional power. (Am J Public Health 1983; 73:96-101.)