BACKGROUND: Data on the prevalence of depression and on how a depressive episode prompts the sufferer to seek primary care are not scarce, but the available evidence on the prevalence of depression among immigrants and poor people who frequent general practice facilities is scarce. The Baudelaire Outpatient Clinic at the Saint-Antoine Hospital in Paris provides free medical and social assistance to the poor and/or uninsured. The goal of our study was to estimate the prevalence of depression among these outpatients, to characterize this depressed population, and to analyze its demand for primary care for depressive episodes. METHODS: From September to December 2010, we conducted a cross-sectional, observational survey among users of the Baudelaire Outpatient Clinic. French-speaking patients attending the clinic between September 15 and December 30, 2010 who agreed to answer a questionnaire administered face-to-face before their consultation were included in the study. The chi-squared test (or Fisher's exact test for small samples) was used for the comparisons of proportions. Logistic regression models were estimated, along with the odds ratios (OR) and their 95% confidence intervals (95% CIs), for the multivariate analysis of factors associated with depression and healthcare-seeking. Models were estimated separately for men and women, since sex was an interaction factor. The statistical analyses were performed using Stata v. 10 software (StataCorp LP, College Station, Texas, USA). RESULTS: Of the 250 patients included (mean age: 45 years), 52.0% were men and 52.4% were immigrants. Close to 40% of them reported having no supplemental health insurance. The estimated prevalence of depression in this population was 56.7%. Depression was more prevalent among the women, immigrants, and people from the poorer socioeconomic groups. Only half of these depressed patients, mostly women, reported having discussed their depression with a physician. French nationality and complete health insurance coverage were associated with more-frequent healthcare-seeking. Few patients reported having been asked about their morale by the physician they consulted, and almost 80% would have liked to be asked about this more often. CONCLUSION: Depression is a real public health problem, particularly among people from disadvantaged backgrounds, and should be included in their overall management.