Drug injection is considered an important issue for the public health of the Republic of Moldova (RM), due to the associated criminality and high rate of social determinated comorbidities. In the period of 2012-2013 a total number of 19400 intravenous drug users (IVDU) were estimated on the left side of the RM and 10800 on the right side. Due to the globalisation of the drug use the development of the legislation that targets the disease prevention due to unsafe drug use, increasing the accessibility to counseling and substitutive treatment was performed. In the RM an important issue is the long duration/systematic use of such drugs: opioids, cocaine and amphetamine. In the EU states the most used drugs are the heroine and other opioids. The drug users are the key population for HIV infection, B and C hepatitis, TB and sexual transmitted diseases. Among Moldovan young adults (18-15 years) the rate of HIV was 8,5%, viral hepatitis 9,1%, TB 1,24% and sexual transmitted infection 12,7% in 2013. The socioeconomic vulnerability of the drug users is due to excessive consumption of drugs, alcohol, unemployment, single civil state, high rate of infractions and detention history. The associated epidemiological threaten due to high TB burden, put IVDU in a continuous danger to acquire infection and get sick. The main objective of the research was to identify the particularities of IVDU with TB and to establish their final treatment outcome. Material and methods: The study methodology had a quantitative and a qualitative component. The clinical study was performed as a retrospective, randomized control study, selective, descriptive research targeting risk factors, microbiological and radiological peculiarities, and treatment outcome of a total number of 267 patients, divided in three groups. The study group (SG) which included 48 TB patients with drug use, the first control group (1st CG) included 34 drug users and the second control group (2nd CG) included 185 new cases with pulmonary TB. Including criteria were: age >18 years, pulmonary TB and drug use were diagnosed by the specialists; in the 1st CG patients were diagnosed by the specialists from the Republican Dispensary of the Narcology. Results: Distributing patients according to the sex, it was established the statistical predominance of men in all three groups, with the highest rate in the 1st CG. So, men were 33 (97,1%) in the 1st CG, 42 (87,5%) in the SG and 138 (74,6%) in the 2nd CG, with a male/female ratio=7/1 in the SG, 33/1 in the 1st CG and 2,9/1 in the 2nd CG. The urban residence predominated in all three groups, with the highest rate in the 1st CG: 100% compared with 139 (75,3%) in the 2nd CG and 35 (72,9%) in the SG. Homeless patients were identified in a similar proportion in the SG and 2nd CG: 8 (16,7%) and 29 (15,6%) respectively. The rate of employed patients was high in the 2nd CG 10 (29,4%), compared with 25 (13,5%) in the 3rd SG and 2 (4,7%) in the SG. Unemployed patients statistically predominated in the SG 43 (89,6%) compared with the 23 (67,6%) in the 1st CG and 124 (67,1%) in the 2nd CG. Poor living conditions predominated in the SG 29 (60,4%) and the 2nd CG 106 (57,3%) compared with the 1st CG 14 (41,2%). Migrants were established only in the 2nd CG 24 (12,9%) and SG 8 (16,7%). History of detention was established in the SG 16 (33,3%) and 1st CG 7 (20,6%). Close TB contact was established in the SG 15 (31,2%) and 2nd CG 15 (8,11%). The HIV infection statistically predominated in the SG 21 (43,7%) compared with 11 (5,9%) in the 2nd CG and 1 (2,9%) in the 1st CG. Viral hepatitis were established only in the 1st CG 6 (17,6%), as well mental disorders 13 (38,2%) compared with 4 (2,16%) in the 2nd CG and 1 (2,1%) in the SG. The final anti TB treatment outcome was expressed through a high rate of lost to follow-up and died in the SG compared with the 2nd CG: 10 (20,8%) against 2 (1,08%) and 8 (16,7) against 11 (5,9%), as well a low success rate 21 (43,7%) against158 (85,4%). Conclusions: Associated risk factors as socioeconomic vulnerability and comorbid state contributed to a poor outcome. Social support and awareness about the free of charge diagnosis and treatment among key populations must be increased for improving the epidemiological state of the Republic of Moldova.