IMPORTANCE Errors and adverse events occur frequently in health care. Three-dimensional (3-D) laparoscopic systems claim to provide more realistic depth perception and better spatial orientation compared with their 2-D counterparts. OBJECTIVE To compare the association of 3-D vs 2-D systems with technical performance during laparoscopic Roux-en-Y gastric bypass (LRYGB) procedures using a multiport intraoperative data capture system. DESIGN, SETTING, AND PARTICIPANTS This cohort study was performed between May and December 2018, with a total of 50 LRYGB procedures performed in an academic tertiary care center; recordings of the operations were evaluated with a 30-day follow-up. All procedures were performed by the same surgical team. EXPOSURE Surgical teams used 2-D or 3-D laparoscopic systems. MAIN OUTCOMES AND MEASURES Technical performance was evaluated using the Objective Structured Assessment of Technical Skill and surgical errors and events using the Generic Error Rating Tool. RESULTS Of the 50 patients who underwent LRYGB procedures, 42 (86%) were women, with a median (interquartile range) age of 42 (35-47) years and a median (interquartile range) body mass index of 46 (42-48), with no significant demographic differences between the groups whose operations were performed using the 2-D and 3-D systems. The mean (SD) number of errors per case was significantly lower in procedures using the 3-D laparoscopic system than in those using the 2-D system (17 [6] vs 33 [2]; P < .001). The mean (SD) number of error-related events was significantly lower in procedures using the 3-D system than in those using the 2-D system (6 [2] vs 11 [4]; P < .001). Mean (SD) Objective Structured Assessment of Technical Skill scores were significantly higher when the 3-D system was used than when the 2-D system was used (28 [4] vs 22 [3]; P < .001). CONCLUSIONS AND RELEVANCE In this limited sample of LRYGB procedures, the use of a 3-D laparoscopic system was associated with a statistically significant reduction in errors and events as well as higher Objective Structured Assessment of Technical Skill scores compared with 2-D systems.