Well leg compartment syndrome (WLCS) is an uncommon and severe complication that occurs after prolonged surgery in the lithotomy position. A 67-year-old male with bladder cancer who underwent cystectomy including ileal conduit construction in the lithotomy position developed severe, gradually worsening cramping pain in the right leg on the day after surgery. The posterior compartmental pressure of the right leg was high (40 mmHg), and WLCS was diagnosed. Emergency fasciotomy was followed by rehabilitation for one month and he recovered from motor or sensory deficits, but the pain continued. We considered that important factors associated with the development of WLCS in this patient were arteriosclerosis obliterans and the length of time during which he remained in the lithotomy position during the ileal conduit procedure. We consider thatlengthy surgical procedures for cystectomy with patients in the lithotomy position have high potential for inducing WLCS.