This paper examines the patient's decision to select a source of care, offers a theoretical construct of this choice process, and reports on the results of a survey that tested the model among the population of Rochester, New York. Respondent reasons for selecting a source of ambulatory care are collapsed into categories that relate to individual perceptions of the utility of cost, time, convenience, sociopsychological factors, and the technical quality of care. The relative importance of these criteria and other findings relating to sociodemographic characteristics and individual patterns of utilization are reported. The data are derived from a survey (N = 521) of households representative of the area of Rochester, New York.