Extraarticular fractures of the pelvic ring after periacetabular osteotomy could impair stability of the acetabular fragment and cause poor clinical and radiographic outcomes. We evaluated 17 patients (17 hips) with fractures of either the ipsilateral os pubis (n = 12) or os ischium (n = 5) during the postoperative period after periacetabular osteotomy. Ischial fractures seemed more debilitating with two of five resulting in painful nonunions for which additional surgery was performed. In contrast, only one patient with pubic fracture had additional surgery. Ischial fractures took almost twice as long to achieve resolution of symptoms compared with pubic fractures, and when left untreated, asymptomatic nonunions developed in three of five. However, we observed no effect on acetabular fragment positioning or long-term clinical outcome. It is essential to be aware of this potential complication and realize it could be accompanied by substantial morbidity for patients during the rehabilitation period after periacetabular osteotomy, but does not seem to influence the longer-term outcome. LEVEL OF EVIDENCE: Level IV, therapeutic study.