We sought to determine whether we could successfully contact patients for follow-up using telephone numbers given during routine emergency department (ED) registration. Every fifth patient visiting our ED during the study period was eligible. Three calls were made to each number. Calls began 7 days after the ED visit. Of 1,136 patients, we successfully contacted 478 (42.1%). Of those patients unreachable across all three attempts, 183 (16.1%) had given wrong numbers, 133 (11.7%) had disconnected lines, and 156 (13.7%) had three consecutive "no answers." Females and patients with nonurgent complaints were significantly more likely to be contacted. Despite stringent calling protocols, we successfully contacted only 42% of our patients. Nearly 28% gave wrong or disconnected numbers. Placing two additional calls to those patients who were not home or did not answer initially nearly doubled the overall contact rate, although similar efforts for patients who initially gave wrong or disconnected numbers yielded no appreciable gains. Females and nonurgent patients were over-represented.