The therapeutic effect of rifampicin 1200 mg once monthly and 100 mg clofazimine daily for the first six months of treatment was evaluated in 30 patients of bacteriologically positive lepromatous leprosy patients. Moderate to marked clinical improvement was seen in all the patients and a very rapid bacteriological regression as indicated by the decrease in bacteriological and morphological indices of the skin within one week. Seven patients become MI negative at one month and three months and 13 at the end of nine months. Two patients became MI and BI negative at the end of six months and six at the end of nine months. These observations clearly establish the high therapeutic efficacy and practicability of the three drug regimen. Once monthly rifampicin is highly effective and well tolerated, and has many advantages like low cost, better patient compliance and reliability of the treatment. Addition of clofazimine to rifampicin and dapsone prevents the emergence of E.N.L. reactions which were seen during treatment with once monthly rifampicin and daily dapsone. This regimen is thus ideal for initial, intensive treatment of lepromatous leprosy and may help in preventing the spread of the disease and development of dapsone resistance.