The most important factor in the effective chemotherapy of the bone and joint tuberculosls is based on the use of sensitive antituberculous drugs. Failure of chemotherapy to control the bone and joint tuberculosis may be caused by drug resistance. For twenty years from 1960 to 1979, we observed and analysed for bacteriological study in terms of primary and acquired resistances in 120 bone and joint tuberculosis patients who yielded positive on culture for AFB. The results were obtained as follows: 1. Cultures for AFB with 412 surgical specimens taken from the tuberculous focl of bone and joints have been carrled out, Out of the 412 patients, 120 cultures for AFB were positive (29.1%) and no significant difference in all years. The cases were then grouped in 5 years for convenience. 2. Of the 120 culture-positive patients, 40.8% had resistance to 1 or more drugs. 3. 23.3% had drug resistance to 1 drug only, 6.7% to 2 drugs and 10.8% to all 3 drugs respectively. 4. Resistant cases to INH, PAS, SM were 25 (20.8%), 32 (26.7%) and 26 (21.7%) respectively. 5. Drug resistances to 1 or more drugs by involved site were 38.8% In spine, 45.8% in hip and 23.3% in knee. 6. Of the 61 patients with no history of previous chemotherapy, 16 (26.2%) had resistance to 1 or more drugs, while ot the 59 patients with history of prevlous chemotherapy, 33 (55.9%) had resistance. 7. Drug resistance was found to be proportionally Increased to the duration of previous chemotherapy, 8. Drug resistance was mainly related to previous history of chemotherapy rather than duration of illness. 9. Obtalning drug resistance to all 3 drugs tends to be increased every-year regardless of prevlous chemotherapy.