The sustained effectiveness in improving resident performance of breast, cervical, and colorectal cancer screening examinations in the medicine outpatient department (OPD) was studied. Residents were divided into two groups: an intervention group, which received lectures presenting cancer screening rationale and recommendations, followed by chart reminders for three months, and a control group with no intervention. Charts were reviewed for cancer screening performance before, and one and six months after the intervention. Results showed increased performance of Pap smears (50% vs 22%, P less than .04 at one month and 46% vs 23%, P less than .08 at six months) and rectal examinations (73% vs 58%, P less than 0.2 at six months) by the intervention group. There was no improvement in breast examination performance over baseline (39%). Other screening examinations were rarely done. Future outpatient practice will include preventive health care, and greater emphasis must be devoted to increasing and sustaining residents' cancer screening performance to improve these results.