We report the successful treatment with ultraviolet B phototherapy of a patient with HIV-associated eosinophilic pustular folliculitis. We were able to observe the clinical and therapeutic course for about one year and three months. This 35-year-old homosexual Japanese man presented with disseminated, discrete, follicular, erythematous papules with intense pruritus over his face, neck, chest wall, and upper back. Initially, the eruption responded to therapy with topical or oral indomethacin and oral H1 antihistamine. However, the eruption was highly prone to recurrence, and it gradually failed to respond to these therapies. The eruption became chronic and persistent and manifested the excoriated, prurigo-like nodules that are typical of reported pruritic papular eruption, suggesting that this skin disease and HIV-associated eosinophilic pustular folliculitis are two forms of the same disease entity. UVB phototherapy in small doses was very effective for the persistent eruption, and no recurrence of the eruption was noted during or since the six-month maintenance therapy (once a week at a dose equivalent to 0.75 of the minimal erythema dose) (9 months total). No unfavorable side effects have been observed during or after the UVB phototherapy (cumulative UVB doses of 2,320 mJ/cm2).