The Edinburgh Postnatal Depression Scale (EPDS) is the screening tool for perinatal depression, and its cut-off score varies according to context and population. In Cameroon, no study has yet defined a cut-off score or the prevalence of perinatal depression in adolescent mothers. Our aim is to determine the cut-off for teenage mothers in Cameroon. The study is cross-sectional and analytical in nature. The EPDS was used to screen for symptoms of depression and an interview based on the DSM-5 criteria for depression was conducted to diagnose the depressive syndrome. The data were processed with Epidata 3.1 and was analysed with SPSS 25. Positive and negative predictive values (PPV, NVP) were calculated. The optimal EPDS score was determined by taking into account the importance of falsenegative and false-positive test results. 1633 adolescent mothers were recruited. The prevalence of perinatal depression was 60.8% (95% CI = 58.5, 63.2). The cut-off score for this population was ≥ 11. Sensitivity was 92.6% (95% CI = 0.913, 0.939) specificity 53.2% (95% CI = 0.508, 0.556), PPV 75.5% and NPV 80.2%. This score of ≥ 11 is retained because false-negative results have important adverse consequences. This study on the validation of the EPDS and the prevalence of perinatal depression in a population of teenage mothers is new in Cameroon and central Africa.