DOPA oxidase activity in the hypopigmented non lepromatous leprosy lesions of various degrees was observed in 15 patients along with a control study. The observations were compared with those of unaffected adjacent parts of the skin in the same patient, depigmented skin of vitiligo and normal skin of a normal subject. The results are indicative of proportionate lack of DOPA oxidase activity in the hypopigmented lesions of leprosy in commensuration with the relative degree of clinical hypopigmentation. Comparatively reduced melanocytic activity in the hypopigmented lesions of leprosy becomes apparent.