It is widely believed that patients' compliance can be increased by persuading them to participate in their own care. We tested whether patients with hypertension could manage their own clinical records and whether their doing so would affect the quality of their care. Two hundred patients were randomly assigned to an intervention or a control group. Those in the intervention group were asked to complete a 10-page booklet containing a personal standardized medical record. All patients were scheduled for a follow-up appointment at the end of one year and were referred to their general practitioners for interim care. At the end of the follow-up period, the proportion of patients seen was comparable in the two groups. More of the patients in the intervention group than in the control group filled out a questionnaire as requested, and more added comments. Within the intervention group, the proportion of patients seen and the fall in systolic blood pressure were significantly higher among the 44 patients who had completed the personal record as requested than among the 57 who had not. Patients who completed the personal record also had fewer compliance problems.