The objective of the present study was to define short-course treatment regimens for PB leprosy and to compare them with the 'classical' dapsone treatment and the WHO-PB regimen. Five treatment regimens were studied and evaluated by the histologic evolution. The regimens were: (1) dapsone 100 mg daily, non-supervised for 3 years; (2) RMP 900 mg supervised, once weekly, 8 doses; (3) idem 12 doses; (4) RMP 600 mg, once monthly, supervised, 6 doses and during this treatment dapsone 100 mg daily unsupervised; (5) RMP 600 mg together with dapsone 100 mg daily, supervised for 6 days. For each of these regimens there were between 114 and 195 person-years of follow-up. Results are comparable for the 5 treatment regimens, and reach 65-75% cure rates at 36 months and 80-90% at 48 months after the start of therapy. The relapse rate for all groups is about 0.5% per year. The difficulty for the diagnosis of relapse in PB leprosy is discussed. It is concluded that treatment of PB leprosy can be relatively simple but that a relatively long time is needed to evaluate its effect.