A comparative study was performed on the initial and final bacillary indexes of 213 multibacillary leprosy patients who received 12 doses (Group 1: 128 patients) or 24 doses (Group 2: 85 patients) of multidrug therapy (MDT/WHO) to measure the effectiveness of the two regimens. All patients were evaluated at treatment baseline, 12 months, and 24 months. The reduction in bacillary levels and mean bacillary indexes at 24 months was similar in the two groups. No statistical difference in reaction rates was observed between the two treatment regimens.