Importance:Colon surgery is associated with a high rate of surgical site infection (SSI), and there is an urgent need for strategies to reduce infection rates. Objective:To assess whether laparoscopic colon surgery is associated with a lower surgical site infection rate than open-approach laparoscopy, especially in patients with medically complex conditions. Design, Setting, and Participants:This cohort study used previously validated diagnosis and procedure codes from Medicare beneficiaries who underwent colon surgery from January 1, 2009, to November 30, 2013. Analyses were performed from August 1 to December 31, 2018. Main Outcomes and Measures:Outcome measures were SSI events, medical comorbidities, and laparoscopic or open approach procedures. Results:A total of 229 726 patients (mean [SD] age, 74.3 [9.4] years; 128 499 [55.9%] female) underwent colon procedures. There were 105 144 laparoscopic procedures and 124 582 open procedures. The overall mean SSI rate was 6.2%, varying by surgical procedure from 5.8% to 7.6%. Among the full study population, adjusted model results showed a significant association of laparoscopy with lower odds of SSI (odds ratio, 0.43; 95% CI, 0.41-0.46; P < .001). When stratified by surgical approach, the mean SSI rates were 4.1% (procedure-specific range, 3.9%-5.1%) for the laparoscopic approach and 7.9% (procedure-specific range, 7.4%-10.2%) for the open approach. When stratified by Elixhauser score groups, the mean SSI rates were 6.2% (procedure-specific range, 3.2%-8.7%) for group 1 (0-1 comorbidity), 5.5% (procedure-specific range, 3.6%-11.1%) for group 2 (2 comorbidities), and 6.6% (procedure-specific range, 4.6%-10.6%) for group 3 (3-13 comorbidities). An interaction was also observed between laparoscopic approach and Elixhauser groups, with increased odds of SSI among patients who had 3 to 13 comorbidities present at the time of the procedure (odds ratio, 1.21; 95% CI, 1.11-1.32) compared with patient groups with fewer comorbidities. The population attributable fraction of SSIs for use of the open approach was 34.2%. A total of 2317 of 3882 hospitals (59.7%) performed few (0%-10%) or most (>50%) procedures laparoscopically. Conclusions and Relevance:Policy changes that promote surgical education and resources for laparoscopy, especially at low-adoption hospitals, may be associated with reduced colon SSI rates. Support of the development of innovative educational policies may help achieve improvement in patient outcomes and decreased health care use in colon surgery.