KEYWORDS laparoscopic surgery, parastomal hernia, peristomal skin disorders, risk factors, stoma-related complications 2 Abstract Purpose: Laparoscopic approach is now a widespread technique used worldwide, but there are few recent studies on risk factors for parastomal hernia. Therefore, this study was performed to analyze the incidence of parastomal hernia in laparoscopic or open loop stoma, and to determine risk factors for parastomal hernia formation. Associations between parastomal hernia and other stoma-related complications were also analyzed. Methods: A retrospective analysis of patient and surgical characteristics was performed in 153 consecutive cases with stoma creation in loop ileostomy or colostomy performed at our hospital from January to December 2016. Results: Parastomal hernia developed in 77 cases (50.3%), including 39 (25.5%) diagnosed by physical examination and 38(24.8%) detected by CT alone. In univariate analysis, a stoma that did not pass through the middle of the rectus abdominis muscle was a significant risk factor for parastomal hernia. This remained as the only independent risk factor for parastomal hernia formation in multivariate analysis. An additional analysis identified a laparoscopic approach as the only independent risk factor for formation of a stoma that did not pass through the middle of the rectus abdominis muscle. An analysis of stomarelated complications showed that peristomal skin disorders were significantly associated with parastomal hernia formation. Conclusions: This study showed that a stoma that is not formed through the middle of the rectus abdominis muscle is a risk factor for parastomal hernia, and that a laparoscopic approach is associated with this risk factor. Moreover, a parastomal hernia is significantly associated with peristomal skin disorders.