This study evaluated estimates of depression symptoms, major depression, alcohol use or disorders and their association with ART adherence in sub-Saharan Africa. Studies published between January 1, 2006 and July 31, 2011 that documented rates of these mental health problems were identified through electronic databases. A pooled analysis of 23 studies reporting rates of depression symptoms and six studies reporting rates of major depression indicated a pooled estimate of 31.2% (95% CI 25.5-38.2%, Tau(2) = 0.23) and 18% (95% CI 12.3-25.8%, Tau(2) = 0.19) respectively. Few studies reported rates of alcohol use or disorders, and so we did not pool their estimates. Likelihood of achieving good adherence was 55% lower among those with depression symptoms compared to those without (pooled OR = 0.45 (95% CI 0.31-0.66, Tau(2) = 0.20, P value = 0.000). Interventions to improve mental health of HIV-positive individuals and to support adherence are desperately needed in sub-Saharan Africa.