to compare testosterone levels between female depressed patients and female bipolar patients. Sixty-one female patients with major depressive disorder (MDD) ( = 23) or bipolar disorder (BD) ( = 38) between 18 and 45 years old were included in the study. Participants were evaluated during a depressive or manic episode with the Hamilton depression rating scale (HDRS) or Young mania rating scale (YMRS), respectively. No patients in the MDD group were taken valproate while in the BD group 14 (36.84%) were taken valproate. Total testosterone (TT) and free testosterone (FT) levels were quantified during the early follicular phase of the cycle, with radioimmunoassay or solid phase enzyme-linked immunoassay. Data were collected from May 2016 to February 2017. Mean TT serum levels were significantly higher in BD patients in comparison to MDD patients. Although age and diagnosis were related to TT levels, however when we added valproate use in the analysis, only the relation between TT and valproate use remained significant. In this sample, TT levels were related to valproate use in patients with BD. More studies regarding the role of testosterone in affective symptoms should be conducted to clarify the relation between testosterone, affective disorders, and medication.KeypointsWe observed that testosterone levels were significant higher in bipolar women compared to women with MDD.The use of valproate could be associated with the testosterone levels in female patients with BD.Evaluation of women suffering BD should include a testosterone levels determination, particularly when they are taking valproate.