Background: In January 2010, the implementation of quality management systems toward WHO-AFRO laboratory accreditation commenced in the Antiretroviral Treatment Laboratory of the Infectious Disease Hospital, Kano, Nigeria. Quality improvement projects were instituted in 2011 in line with ISO 15189 requirements for accreditation of medical laboratory. In this study we evaluated the performance of the laboratory through some set of quality indicators (QI). Methodology: This was a retrospective study to evaluate laboratory QIs monitored from January 2011 to December 2013. The QIs were specimen rejection rate (SSR), turnaround time (TAT), proficiency testing performance (PTP) and client satisfaction survey (CSS). Data was collected into an excel file for analysis and percentage performance compared among years. SSR & TAT were evaluated with the Sigma scale. Results: A total of 7920 (2194 in 2011, 2715 in 2012, 3011 in 2013) specimens were received for testing. 22 (0.28%) specimens were rejected and 81 (1.02%) specimens' results were reported after the acceptable TAT, giving a Sigma level of 4.27 and 3.82 for SSR and TAT respectively. There was steady improvement in PTP: CD4+ from 67% in 2011 to 90% in 2013, hematology from 81% in 2012 to 83% in 2013, blood film reading 79% in 2011 to 83% in 2013 and chemistry from 90% in 2011 to 93% in 2013. HIV serology recorded 100% throughout. CSS increased from 59% in 2012 to 78% in 2013. However, there was no statistically significance difference reported for PTP and CSS over the years (P > 0.05). Conclusion: The study highlights the need to continuously evaluate QIs and calls for more effort to improve on PTP and focuses on understanding and improving on clients concerns.