• The findings suggested inequity in access to drug treatment for depression in a middle-income country, especially for non-white individuals and those from lower social economic status brackets. • Public policies should be developed on primary health care services to optimize the detection and treatment of depression. • Polypharmacy was strongly associated to use of antidepressants. • Optimizing pharmacotherapy can minimize harm and undesired drug interactions. Background: Antidepressants are widely prescribed, and it is important to describe their use characteristics. We aimed to estimate the prevalence of antidepressant use and identify associated factors in a cross-sectional study from a middle-income country. Methods: Participants (n=8,803) from the National Survey on Access, Use, and Promotion of the Rational Use of Medicines in Brazil, a cross-sectional study with a representative sample, were asked about the use of any medicines in the past 30 days. Through the answers, we classified the antidepressants users and non-users. The association between antidepressant use, demographic and clinical characteristics was evaluated. Results: The prevalence of antidepressant use was 6.8% (95% CI 6.2 - 7.3). Most users whom self-reported a previous diagnosis of depression (70.6%) did not report antidepressant use, suggesting underuse. Fluoxetine and amitriptyline ranked first in use. White females, from higher economic status, self-reporting a previous diagnosis of depression, in polypharmacy and in use of psychotropics, with alcohol abstinence, were more likely to use the medicines. Limitations: The use of drugs was measured by self-report, which might have underestimated results. Indication for antidepressant use in depression or other conditions was not investigated. Conclusions: The prevalence of antidepressant use observed in Brazil is lower than in the USA and some European countries. Although patients have a universal right to health in Brazil, improved primary care actions are required to ensure access to treatment of depressive disorders, especially for non-white individuals and those from lower social-economic status brackets.