Using theory and methods from cognitive anthropology, this article examines, in a two-step analysis, the degree to which health care decisions made by elderly Medicare recipients coincide with the norms of physicians. First, consensus theory (Romney et al. 1986) was used to establish that physicians specializing in geriatrics agreed which among many symptoms experienced by elderly patients should receive medical attention. By asking 22 physicians to rate the medical necessity of physician visits for 106 symptoms, a key was developed to assess which patient treatment decisions were deemed "biomedically appropriate" by physicians. Second, a comparison was made between the treatment decisions deemed biomedically appropriate by physicians and 2,091 actual decisions reported by 885 elderly study participants. This comparison showed, in the aggregate, that the treatment decisions made by the elderly study participants are congruent with the norms of the physicians. Rationales given by the elders for their treatment decisions are discussed using an ethnographic decision modeling framework in an effort to understand the patterning of criteria they used to arrive at biomedically appropriate and inappropriate decisions.