To examine the bacteriological profile and the prevalence of drug resistance among patients attending the health facilities where the District Tuberculosis Programme (DTP) was in operation with short-course chemotherapy (SCC) regimens, sputum specimens were collected on admission and the end of treatment in North Arcot district and Pondicherry region. In North Arcot district, rifampicin, isoniazid and pyrazinamide were given twice weekly for the first 2 months followed by rifampicin and isoniazid twice a week for the next 4 months under fully supervised administration. In Pondicherry, rifampicin, isoniazid and pyrazinamide were given daily for the first 2 months followed by rifampicin and isoniazid twice weekly for the next 4 months. Of the patients who had received 80% or more of the drugs, 80% from North Arcot and 92% from Pondicherry were rendered culture-negative for Mycobacterium tuberculosis at the end of treatment. Even among patients with initially resistant bacilli, a high proportion had a favourable response. Before start of treatment, of the 2779 patients from North Arcot, 25% had resistance to one or more drugs including 2% with resistance to rifampicin. In Pondicherry, 13% of the patients had initial resistance to one or more drugs. Initial resistance to rifampicin was observed in 0.9%. None of the initially drug-sensitive patients had acquired resistance to rifampicin at the end of treatment.