Background: In Nigeria, it is estimated that about 1.9 million people were living with HIV in 2019, with a national HIV prevalence of 1.4% among adults aged 15-49 years. HIV status disclosure and adherence to Highly Active Antiretroviral Therapy (HAART) medication is important for the prevention and control of HIV/AIDS. Several factors have been identified as being associated with increased adherence to HAART including HIV status disclosure. Disclosure of HIV status pose a great challenge in our society due to associated stigma and other negative consequences. The aim of this study was to explore the relationship between HIV status disclosure and adherence to HAART. Methods: The study was a cross-sectional analytical study involving 361 adults aged 18 years and above attending the Antiretroviral Therapy Clinic of the Federal Medical Centre Keffi. Subjects were randomly recruited by systematic random sampling. Informed consent was obtained and data on socio-demographic, HIV status disclosure, adherence to HAART and WHO clinical staging were collected using a structured pre-tested questionnaire. Data on viral load and CD4 cell count were determined through blood sample analysis. Results: Three hundred and sixty-one PLWHA were analysed, of whom 306(84.8%) had disclosed their HIV status. The mean age of the participants were 39.75 ± 10.00 years with majority aged between 30 to 39 (41.8%). Majority of the participants were female (301;83.4%) with male to female ratio of 1:5. Disclosure rate was more in males (54;90.0%) than females (252;82.4%). There was a significant association between HIV status disclosure and age (p-value=0.04), source of income (p-value= <0.001), use of contraceptive for females (p-value= <0.001), case manager (p-value= <0.001), perceived general state of health (p-value= <0.001) and plans for future pregnancy (p-value=0.030). Also, HIV status disclosure had a significant positive effect on adherence to HAART (p-value= <0.001). Participants who ...