BACKGROUND: Although opportunities for patients to review their medical records are increasing, nothing is known about which patients want to take advantage of those opportunities. The objective of this study was to determine the proportion and characteristics of patients who are very interested in examining their clinic medical record and the reasons for their interest. METHODS: Cross-sectional, mailed survey (conducted in May 2001) to a random sample of 4500 adults who had a recent clinic visit. RESULTS: The response rate was 81%; 36% were very interested in reading their medical record (dependent variable). In multivariate logistic regression, the significantly related factors were seeking health information (finding the Internet very important for health information [adjusted odds ratio, 2.09], having a health newsletter subscription [adjusted odds ratio, 1.23], and using a health resource book in last month [adjusted odds ratio, 1.36]); being very concerned about errors in care (adjusted odds ratio, 2.52); and lacking trust in their physician (adjusted odds ratio, 1.55). Health status, use of health care, education, and income were not independently related to patients' interest. The most common reasons for patients wanting to look at their medical record were to see what their physician said about them (74%), to be more involved in their health care (74%), and to understand their condition better (72%). CONCLUSIONS: Patients' interest in reading their medical record is better predicted by their consumer approach to health care than it is by their clinical characteristics. Demographic characteristics of sex and race were related, while socioeconomic factors of education and income were not.