Disclosure of HIV serostatus remains an important tool for the prevention of new infections and early initiation of treatment for HIV-positive individuals' regular sexual partners. Our aim is to identify factors associated with disclosure to partner in patients taking antiretroviral treatment, with a gender- and sex-based approach. In this study conducted in Mali and Burkina Faso, men (154) and women (164) who reported being in a marital or cohabitating relationship were included. Sex-specific bivariate analyses and multivariate logistic regression were performed to identify determinants of disclosure. Disclosure to partner was 72.1% in men and 79.9% in women. Results of bivariate and multivariate analyses indicated that cohabiting with partner was strongly associated with disclosure in both men and women. In men only, older age, literacy and having good communication with the treating doctor were significantly associated with disclosure. Among women, disclosure was associated with having children and high self-reported importance of religion. Future research and interventions promoting disclosure should take into account these differences reflecting the social construction of gender roles in these settings.