<p>Objectives: Parastomal hernia (PSH) is a common complication of colostomy; however, its risk factors remain poorly investigated. In this study, we examined the associations between sarcopenia, visceral and subcutaneous fat, and PSH in patients who underwent transperitoneal colostomy for colorectal cancer.</p><p>Methods: This retrospective, single-center, cohort study included 60 patients who underwent laparoscopic or robot-assisted abdominoperineal resection or Hartmann's procedure for colorectal cancer between November 2010 and February 2022. Stoma creation was uniformly performed using the transperitoneal approach, and PSH was diagnosed via abdominal computed tomography (CT) at 1 year postoperatively. Visceral fat areas (VFAs) and subcutaneous fat areas (SFAs) were measured through preoperative CT images using an image analysis system. Risk factors for PSH were retrospectively analyzed.</p><p>Results: PSH was diagnosed in 13 (21.7%) patients. In the univariate analysis, PSH was significantly associated with body mass index >22.3 kg/m² (p=0.002), operation time >319 min (p=0.027), estimated blood loss >230 mL (p=0.008), postoperative complications (p=0.028), stoma diameter >18.6 mm (p=0.015), VFA >89.2 cm² (p=0.005), and SFA >173.2 cm² (p=0.001). Multivariate analyses confirmed that SFA >173.2 cm² (odds ratio: 16.7, 95% confidence interval 1.29-217.2, p=0.031) was an independent risk factor for PSH.</p><p>Conclusions: Subcutaneous fat area is significantly associated with the development of PSH after transperitoneal colostomy. Applying these insights could help to prevent PSH.</p>