We retrospectively evaluated the effectiveness of desensitization therapy for antituberculous drugs (Rifampicin and Isoniazid) in 28 cases (29 episodes) with adverse reactions to these drugs. Desensitization therapy for RFP was performed in 23 cases (24 episodes) with administration of a first dose of 1-150 mg and a final dose of 300-450 mg for 1-29 days. The success rate of this therapy was 79% (19 of 24 episodes). Desensitization therapy for INH was performed in 12 cases with administration of a first dose of 2.5-100 mg and a final dose of 200-400 mg for 3-25 days. The success rate of this therapy was 83% (10 of 12 cases). Based on a comparative study of cases between successful and unsuccessful desensitization to RFP and INH it was concluded that there were no significant differences with regard to allergic history, adverse effects and their periods of appearance, the first dose and final dose of administration and the interval of administration, starting periods of the desensitization therapy and the periods of appearance of adverse effects due to this therapy. We evaluated desensitization therapy for two antituberculous drugs (RFP and INH) for tuberculous patients for whom the use of such drugs was restricted because of adverse effects, and we found it is a useful treatment, showing a high rate of success (80%).