Abstract: Objective To explore the exist of L-form Mycobacterium bacilli in the lesions of bone and joint tuberculosis.Methods After N-Acetyl-L-Cystein-Sodium Hydroxide (NALC-NaOH) decontamination and Z-N stains,the specimens collected from the lesions were inoculated in L-J culture media,Bactec 460 and L-form broth media for detecting the Mycobacterium bacilli and L-form of Mycobacterium bacilli.Results The L-form of Mycobacterium bacilli were found in the lesions of 11(18.3%) osteoarticular tuberculosis patients.The smear positive rate of smear and L-J culture positive were 9 cases (15%) and 3 cases (5%) respectively.The positive rate of Bactec 460 was 12 cases (20%).Conclusion It is necessary to make L-form Mycobacterium bacilli examination for retreatment tuberculosis patients.

Key words: Mycobacterium bacillus, L-form, Osteoarticular, Tuberculosis