BACKGROUND: It is assumed that the performance of more senior residents is superior to that of interns, but this has not been assessed objectively. OBJECTIVE: To determine whether adherence to national guidelines for outpatient preventive health services differs by year of residency training. DESIGN: Cross-sectional study. PARTICIPANTS: One hundred twenty Internal Medicine residents, postgraduate year (PGY)- 1 and PGY -2, attending a University Internal Medicine teaching clinic between June 2000 and May 2003. MEASUREMENTS: We studied 6 preventive health care services offered or received by patients by abstracting data from 1,017 patient records. We examined the differences in performance between PGY-1 and PGY-2 residents. RESULTS: Postgraduaute year-2 residents did not statistically out-perform PGY-1 residents on any measure. The overall proportion of patients receiving appropriate preventive health services for pneumococcal vaccination, advising tobacco cessation, breast and colon cancer screening, and lipid screening was similar across levels of training. PGY-1s outperformed PGY-2s for tobacco use screening (58%, 51%, P=.03). These results were consistent after accounting for clustering of patients within provider and adjusting for patient age, gender, race and insurance, resident gender, and number of visits during the measurement year. CONCLUSIONS: Overall, patients cared for by PGY-2 residents did not receive more outpatient preventive health services than those cared for by PGY-1 residents. Efforts should be made to ensure quality patient care in the outpatient setting for all levels of training.