Background : The prevalence of depression in the general population is 5 to 10% but can exceed 50% in the most socially vulnerable populations. The perceptions of this disease are widely described in the literature, but no research has been carried out in France to explain the reasons for not consulting a general practitioner during a depressive episode, particularly in people in the most precarious situations. The objective of this study was to describe the reasons for not seeking primary care during a depressive episode in a socially vulnerable population. Methods : An exploratory sequential design with a preliminary qualitative study using a phenomenological approach. Subsequently, themes that emerged from the qualitative analysis were used in a questionnaire administered in a cross-sectional observational study at a free outpatient clinic in Paris in 2010. Lastly, a logistic regression analysis was performed. Results : The qualitative analysis revealed four aspects that explain the non-consulting of a general practitioner during a depressive episode: the negative perception of treatment, the negative perception of the disease, the importance of the social environment, and the doctor-patient relationship. The quantitative analysis showed that close to 60% of the patients who visited the free clinic were depressed and that only half of them had talked with a care provider. The results of the statistical analysis are in line with those of the qualitative analysis, since the most common reasons for not seeing a general practitioner were the negative perception of the disease (especially among the men and foreigners) and its treatments (more often among the men and French nationals). Conclusions : Close to 50% of the depressed individuals did not seek primary care during a depressive episode, and close to 80% of them would have liked their mental health to be discussed more often by a health professional. Better information on depression and its treatments, and more-systematic screening by primary care personnel would improve the treatment of depressed patients, especially those in the most precarious situations.