Purpose-Parastomal hernia (PH) is a frequent complication from stoma formation after radical cystectomy (RC). We sought to determine the prevalence and risk factors for developing PH following RC.Material and Methods-Retrospective study of 433 consecutive patients who underwent open RC and ileal conduit between 2006-2010. Postoperative cross-sectional imaging studies performed for routine oncologic follow-up (n=1736) were evaluated for PH, defined as radiographic evidence of protrusion of abdominal contents through the abdominal wall defect created by forming the stoma. Univariable and multivariable Cox regression analyses were used to determine clinical and surgical factors associated with PH.Results-Complete data were available for 386 patients with radiographic PH occurring in 136. The risk of developing a PH was 27% (95% CI 22-33%) and 48% (95% CI 42-55%) at 1 and 2 years. Clinical diagnosis of PH was documented in 93 patients and 37 were symptomatic. Of 16 patients with clinical PH referred for repair, 8 had surgery. On multivariable analysis, female gender (HR=2.25, 95%CI 1.58-3.21; p<0.0001), higher BMI (HR=1.08 per unit increase 95%CI 1.05-1.12; p<0.0001), and lower preoperative albumin (HR=0.43 per g/dl, 95%CI 0.25-0.75; p=0.003) were significantly associated with PH.Conclusions-The overall risk of radiographic evidence of PH approached 50% at 2 years. Female gender, higher BMI, and lower preoperative albumin were most associated with developing PH. Identifying those at greatest risk may allow for prospective surgical maneuvers at the time of initial surgery, such as placement of prophylactic mesh in selected patients, to prevent the occurrence of PH.