Antiretroviral (ART) treatment failure is a major obstacle in the management of HIV positive clients. This study was carried out to determine the prevalence of ART treatment failure among HIV positive clients attending Aminu Kano Teaching Hospital. The study was conducted by assessing immunological (CD4 cells count) and virological (viral load test) parameters. Of the 120 HIV positive clients tested, 27 (22.5%) had immunological failure while 7 (5.8%) had virological failure. Overall, 5 (4.1%) met the criteria for treatment failure. There was no significant difference between CD4 cells count at first and second visits (P = 0.118; P > 0.05). There was also no significant difference between viral load at first and second visits (P = 0.671; P > 0.05). When subjected to correlation analysis, the study showed negative correlation between CD4 cells count and Viral load test (r = -0.68201). The number of clients with treatment failure deduced from the research is ascribed to non-adherence of clients to medication, which is a major obstacle in the treatment and management of positive clients. Plans to counter this obstacle are highly recommended. Government and concerned organizations can also greatly make a positive impact with regards to the cost of the tests carried out so as to ensure adequate monitoring of HIV patients’ health status. Key words: Treatment failure, HIV, CD4, Viral load, Kano.

Keywords: Antiretroviral Treatment