Background. We examined patient outcomes for colon resection to determine if they varied according to surgeon-specific factors including: (1) American Board of Surgery (ABS) certification, (2) colorectal surgery subspecialty certification, (3) site of residency training (university-based vs nonuniversity-based), and (4) years of experience since ABS certification. Methods. We performed a retrospective study of 15,427 admissions of northern Illinois residents who underwent segmental colon resection as their primary operation from 1994 to 1997 at 76 nonfederal Illinois hospitals. There were 514 surgeons. Main outcome measures were inpatient mortality, complications, and hospital length of stay. Regression analyses with mixed effects were used to assess the significance of surgeon-specific variables as a predictor of outcomes after risk adjustment for patient age, gender, emergency admission, surgeon volume, hospital site, colon pathology, and comorbid illnesses. Results. ABS-certification was associated with reduced mortality and morbidity. Increasing years of experience was associated with reduced mortality. Colorectal surgery certification and site of residency training did not significantly affect outcomes. Conclusion. We were able to link patient outcomes with surgeon's training. Certification was an important determinant of patient outcomes for colon resection. Increasing surgeon experience also had a favorable effect on outcomes, suggesting a continued learning curve subsequent to residency. (Surgery 2002;132:663-72).