OBJECTIVE: This study aimed to determine whether specialized surgeon practice improves clinical outcomes for major inpatient adult colorectal resections. DESIGN: The Nationwide Inpatient Sample was queried for elective colorectal resections performed from 2001 through 2007. Specialization was determined by first identifying surgeons' procedures as either colorectal or noncolorectal. Surgeons were then stratified as either a specialized surgeon, if colorectal cases comprised more than 75% of their caseload, or a nonspecialized surgeon if colorectal cases comprised less than 75%. MAIN OUTCOME MEASURES: The data points collected for these cases were: cost, length of stay, mortality, demographics, comorbidities, acuity of admission, hospital region, hospital location and teaching status, and primary payer information. Cost and length of stay were analyzed using a linear regression model with a log transformation for length of stay. A logistic regression analysis was performed for mortality. These models were adjusted for all other covariates including surgeon volume. RESULTS: A total of 13,925 surgeons performing 115,540 procedures were analyzed. Specialized surgeons comprised 4.6% of surgeons and performed 17.0% of resections. In multivariate analysis, specialized surgeons had a lower risk of mortality (OR 0.72; CI 0.57- 0.90, P = .0044), decreased length of stay (absolute difference in days 0.23; CI 0.11- 0.49, P = .0022), and similar hospital cost (absolute cost difference $420 less; CI $238 more to $1079 less, P = .211) compared with nonspecialized surgeons. Although cost was not significant at a 75% specialization cutoff, a relationship exists between lower hospitalization cost and increased surgeon specialization even when controlled for surgeon volume. CONCLUSIONS: Surgical specialization leads to reductions in mortality, hospital days, and cost for inpatient colorectal care. © The ASCRS 2011.