Sputa of 200 treatment failure cases of pulmonary tuberculosis over a period of 1991-1995 were subjected to culture and sensitivity testing against commonly used anti-tuberculosis drugs. Out of 200 cases, 75% revealed resistance to one or more anti-TB drugs, resistance to isoniazid was observed in 72% cases, it was 49% for rifampicin, and 37% for streptomycin, while the resistance rate for other drugs was low. Majority of patients had resistance to two or three drugs concomitantly while resistance to 4, 5 and 6 drugs was of very low order and resistance to reserved drugs like kanamycin, ethionamide and cycloserine was encountered infrequently (1%). Out of 200 treatment failure patients multidrug resistance (MDR) was seen in 59% cases as 16% revealed resistance to isoniazid alone and strains in 22% cases were sensitive to all drugs. The study concludes that acquired MDR against first line antituberculosis drugs had increased as significant resistance against 3 drug combinations was observed although resistance against 2 drugs concomitantly was insignificant. Most ominous acquired drug resistance was seen against rifampicin in our region. The trends of drug resistance in the country and Haryana State are compared and their implications on outcome of chemotherapy are discussed.