In the Harborview Medical Center pediatrics clinic, we were interested in testing whether a phone call would increase appointment-keeping behavior and whether the call would have a differential effect depending on the interval between appointments. Ninety-eight patients were studied who had scheduled appointments 3 to 264 days in advance and still had these appointments 3 days prior to appointment time. Patients who were randomly placed in an experimental condition received a reminder call. Control patients received no call. The results indicate some difference between compliance rates of the experimental and control conditions in the expected direction (X2=3.715, df=1, p less than .05). Patients whose visits were scheduled more than 14 days prior to the appointment time ("long-interval" patients) were separated from patients whose appointments were scheduled more recently. A significant difference in appointment-keeping rates between the experimental and control groups was found (X2=4.908, df=1, p less than .025), but only for the "long-interval" patients. Therefore, the use of a phone cue is particularly recommended for these patients.