Pyoderma gangrenosum is uncommon neutrophilic dermatosis characterized by richness of the mature neutrophilic polynuclear dermal infiltrate. Pyoderma gangrenosum is associated with variable diseases, most commonly inflammatory bowel disease, hematological diseases, malignancies, but it is reported rarely in rheumatoid arthritis. We report a case of pyoderma gangrenosum in rheumoid arthritis patient. A 50-year-old woman admitted to our hospital due to painful pretibial ulcerative skin lesions. She had been treated as rheumatoid arthritis for 8 years. At admission, body temperature was $36.5^{circ}C$ and other vital sign was unremarkable. Physical examination revealed right pretibial ulceration, multiple pustules on left pretibial area and both palms. Laboratory studies revealed WBC count 7,600/uL (neutrophils 60.3%, eosinophil 3.2%), hemoglobin 11.4 g/dL, platelet count 319,000/uL, ESR 65 mm/hour. Other lab findings were also unremarkable. Skin biopsy was done, which showed dense dermal infiltrate of neutrophils and wound culture were negative. By 8 weeks after systemic high dose corticosteroid (1 mg/kg/day), cyclosporine A (5 mg/kg/day), sulfasalazine 2 g therapy, symptoms and skin ulceration were being improved. Without skin relapse, she is followed up our hospital with low dose corticosteroid and sulfasalazine.