Patient education is receiving increasing interest from persons interested in improving adherence to regimens and in preventing disease. Yet a number of empirical studies have cast doubts on the notion that patient education actually can influence behavior. This article compares and contrasts two paradigms of patient education, one based on the teaching approach and the other based on a behavioral diagnosis. The behavioral diagnosis is the assessment of influences on the desired patient behavior. It includes consideration of individual, social, environmental, and medical regimen factors that may either impede or facilitate behavior. The process of performing a behavioral diagnosis is presented, and clinical experience using this approach is described.