Patients who fail to show for scheduled visits or who fail to contact their provider when warning symptoms occur pose important problems for the primary care physician. A group of interventions was examined to determine the effectiveness in increasing the number of prescribed office visits in patients with diabetes mellitus. This group of interventions included mailed packets with information on how to use the clinic, providers' names and phone numbers, after-hours phone numbers, a list of early warning signs, and a booklet on managing diabetes mellitus; mailed appointment reminders; and intense follow-up of visit failures for prompt rescheduling. Eight hundred fifty-nine patients on drug therapy for diabetes mellitus were stratified by risk of hospitalization and randomly assigned within strata to control and intervention groups. The intervention group received all interventions. After 1 year, the intervention group averaged 12% more total contacts than the control group (5.8 vs. 5.2, P = 0.01), due largely to an increase in kept scheduled visits (4.1 vs. 3.6, P = 0.006). These effects were greatest in those patients at higher risk of hospitalization. Also, visit failures were reduced only in high-risk patients. The effect of the interventions did not diminish during the year of study. This systematic and repetitive intervention appears effective in increasing prescribed office visits and is especially effective in patients requiring more frequent care.