Pyoderma gangrenosum is an extremely rare chronic cutaneous disease causing severe ulceration. It can be developed after minor trauma or surgical procedure. The typical features mimic acute infection site, however the treatment methods are opposing since pyoderma gangrenosum is improved with the use of corticosteroids, not antibiotic therapy. We here report a patient who had been diagnosed for acute infection after cesarean delivery in 2011 and treated with a number of antibiotics, but failed to recover. The patient had suffered from pain of the disease and also renal failure caused by antibiotics. Ultimately she had been diagnosed as pyoderma gangrenosum and managed successfully with steroids. For her next pregnancy in 2013, we tried vaginal delivery after prior cesarean section and it was uneventful during and after delivery.