Objective Despite the importance of dietary factors in treating and preventing heart disease, relatively little work has explored how well cardiac patients understand the nutrition information they are given. This study was designed to assess the nutrition knowledge and attitudes of cardiac patients.Design An onsite survey was administered to patients who were waiting to see their cardiologists. The survey focused on patients' medical history, attitudes toward nutrition, and knowledge of ''heart-healthy'' dietary information.Setting Cardiology practices in New England, Southern California, and the Midwest.Subjects A total of 606 patients completed the survey (roughly 74% of those approached).Results Most patients rated dietary factors as extremely important in treating and preventing heart disease, and 67.0% of those who had experienced a heart attack reported believing that diet had played a contributing role. Nonetheless, nutrition knowledge was marginal. Despite the fact that 92.4% of patients reported receiving dietary literature, overall accuracy rates on responses to nutrition questions did not exceed chance levels. Only 30.5% of the patients who were given dietary literature reported understanding it completely.Conclusions Nutrition counseling should receive higher priority, both in medical training and in patient care, and cardiac patients should be referred to dietitians on a more routine basis. Physicians should not assume that patients who are given dietary information understand the materials they receive. J Am Diet Assoc. 1995; 95:442-446.