Despite randomized controlled trials and meta-analyses, it remains unclear whether laparoscopic pyloromyotomy (LP) carries a higher risk of incomplete pyloromyotomy and mucosal perforation compared with open pyloromyotomy (OP).Multicenter study of all pyloromyotomies (May 2007-December 2010) at nine high-volume institutions. The effect of laparoscopy on the procedure-related complications of incomplete pyloromyotomy and mucosal perforation was determined using binomial logistic regression adjusting for differences among centers.Data relating to 2830 pyloromyotomies (1802 [64%] LP) were analyzed. There were 24 cases of incomplete pyloromyotomy; 3 in the open group (0.29%) and 21 in the laparoscopic group (1.16%). There were 18 cases of mucosal perforation; 3 in the open group (0.29%) and 15 in the laparoscopic group (0.83%). The regression model demonstrated that LP was a marginally significant predictor of incomplete pyloromyotomy (adjusted difference 0.87% [95% CI 0.006-4.083]; P=0.046) but not of mucosal perforation (adjusted difference 0.56% [95% CI -0.096 to 3.365]; P=0.153). Trainees performed a similar proportion of each procedure (laparoscopic 82.6% vs. open 80.3%; P=0.2) and grade of primary operator did not affect the rate of either complication.This is one of the largest series of pyloromyotomy ever reported. Although laparoscopy is associated with a statistically significant increase in the risk of incomplete pyloromyotomy, the effect size is small and of questionable clinical relevance. Both OP and LP are associated with low rates of mucosal perforation and incomplete pyloromyotomy in specialist centers, whether trainee or consultant surgeons perform the procedure.