We report the case of a patient with autosomal dominant polycystic kidney disease (ADPKD) and an insufficiency-type fracture of the pelvis. A 60-year-old Japanese woman was admitted because of pain in the right ischium and pubis that began suddenly with no precipitating cause. Computed tomography showed the bony pelvis to be compressed by enlarged dependent kidneys and an enlarged liver. We relieved compression on the pelvic bones by means of transarterial embolization (TAE) to the kidneys and liver after initiation of hemodialysis therapy. The fracture healed gradually after TAE, and the patient could walk 4 months later. In an iliac bone specimen obtained before TAE, cancellous bone was intact, but periosteal and endosteal surfaces of cortical bone showed marked resorption and were irregular. Normally, many ligaments are connected tightly to the periosteal surface, supporting the cortical bone. However, because of extensive surface resorption associated with pressure from enlarged kidneys, connections between ligaments and the periosteal surface presumably became fragile, promoting an insufficiency fracture from unapparent external forces. Thus, ADPKD is a potential cause of insufficiency fracture owing to abnormalities of cortical bone.