Pyoderma gangrenosum is a rare chronic ulcerative noninfectious disease of the skin. Half of patients are complicated with other autoimmune diseases, most commonly inflammatory bowel disease, Takayasu disease, and rheumatoid arthritis. It has been reported that approximately 4% of them were childhood-onset. The conventional treatments of pyoderma gangrenosum were described as systemic corticosteroids and cyclosporine. The combination of corticosteroids with immunosuppressants such as tacrolimus, mycophenolate mofetil has been reported as steroid-sparing modalities. We herein reported a girl, 12 years of age, having pyoderma gangrenosum refractory to the conventional combination of systemic prednisolone with cyclosporine, but successfully treated with infliximab, the anti-TNFalpha monoclonal antibody. Rapid improvement of pyoderma gangrenosum was seen within three doses of infliximab infusion. All skin lesions eventually healed completely and new skin ulcers were never coming out again. The dramatical improvement suggested that infliximab should be considered for patients with refractory pyoderma gangrenosum though further experiences and investigations are required to determine the mechanism of infliximab.