Erythema nodosum is a panniculitis that has been reported in association with bacterial, fungal and viral infections, medications, malignancies, autoimmune diseases, and other inflammatory disorders, especially sarcoidosis and inflammatory bowel disease. Erythema nodosum is not an uncommon dermatologic entity. However erythema nodosum associated with pulmonary tuberculosis has not been reported by Korean dermatologists. The patient was a 18-year-old female who presented with tender subcutaneous erythematous nodules on the both shin for 1 week. She had been diagnosed as pulmonary tuberculosis at 1 year ago. She was treated at local clinic with anti-tuberculosis therapy, but she self-discontinued treatment. Chest X-ray and CT demonstrates pulmonary nodules. Histopathological examination of a skin biopsy specimen from the lesion revealed edematous and fibrotic septa of the subcutaneous fat layer with a septal infiltrate that includes lymphocytes, histiocytes, neutrophils, and eosinophil. We diagnosed this case as erythema nodosum associated with pulmonary tuberculosis on the basis of above clinical and histopathological examination. The patient was treated with anti-tuberculosis therapy. The skin lesions improved within 1 month and no lesion was observed during 3 months of follow up.