Background: Identification of members in the Mycobacterium Tuberculosis Complex (MTBC) is essential for monitoring the epidemiology of tuberculosis (TB) and implementing appropriate public health control measures as the members tend to differ in their epidemiology, host range, pathogenicity, geographic distribution, and drug resistance patterns. Methodology: Molecular speciation for confirmation of the MTBC species was performed by GenoType MTBC assay (Hain Lifescience, Nehren, Germany) and drug susceptibility testing (DST) for both treatment groups was performed by the MGIT 960 system. Results: Of the 405 TB clinical isolates 391(96.5%) were members of MTBC and 14 (3.5%) were NTM. Of the MTBC 391(100%) were M. tuberculosis, other members of MTBC (e.g. M. africanum, M. bovis, M. bovis BCG, M. caprae and M. microti) were not found. DST for SIRE was performed for 262 TB clinical isolates of patients who were subjected to the first line anti-TB treatment regime. Among these, 60 (22.9%) were resistant to at least one anti-TB drug; 32 (12.2%) of the total isolates were mono resistant strains while 8(3.1%) patients had poly resistant strains. INH showed a resistance of 35(13.4%). Twenty patients (7.6%) who were treated with the first line anti-TB regime were found to be MDR-TB cases. Of the 66 MTB clinical isolates which were identified as MDR-TB prior to initiation of anti-TB treatment and subjected to DST of the two first line anti-Tb and MDR-TB treatment drugs; PZA and EMB, 43 (65.2%) were resistant to PZA and 28(42.4%) to ethambutol. Twenty three (34.8%) of the MDR-TB isolates were resistant to both PZA and ethambutol. Conclusion: M. tuberculosis is by far the major MTBC species causing pulmonary TB in northern Tanzania; however a proportion of cases treated as TB are actually NTM. INH resistance is the highest among anti-TB drugs and denotes the high potential for developing MDR-TB. A proportional of patients on empirical first line anti-TB treatment x are in fact MDR-TB patients. The rate of resistance to PZA and EMB in the MDR-TB patients is alarming. Key words: tuberculosis, Monoresistance, Polyresistance, Multi drug resistance, drug susceptibility pattern, Pyrazinamide.