Mycosis fungoides is the most common cutaneous T-cell lymphoma, accounting for more than 40% of all primary cutaneous lymphomas. Clinically, it is characterize by the presentation of patches, plaques and tumors, depending on the disease stage. A 38-year-old man presented with scaly erythematous round patch on left temporal scalp. He recognized the lesion 3 months ago. And he applied steroid ointment for 2 weeks but lesion did not change. The patient had no medication history. We performed histopathologic examination and immunohistochemically stain. On the histopathological examination, the specimen of the lesion showed Prominent infiltrate of small to medium sized lymphocytes with epidermotropisom, and Pautrier microabscess. We could diagnosis as mycosis fungoides and treated with psoralen ultraviolet A therapy. Solitary mycosis fungoides is a variant characterized by a single lesion involving less than 5% of the body surface skin area. It is clinically and histopathologically indistinguishable from classic mycosis fungoides. Established and most widely used therapies for solitary mycosis fungoides include radiotherapy or surgical excision. However, there have been reports of poor effects or side effects. Ultraviolet light is a long established treatment for mycosis fungoides. Herein, We reports solitary mycosis fungoides of scalp treated with psoralen ultraviolet A therapy, rarely reported in Korean literature.