Résumé : Background Integrating mental health care into the primary care system is an important policy option in the Democratic Republic of the Congo (DRC). From the perspective of the integration of mental health care in district health services, this study analyzed the existing demand and supply of mental health care in the health district of Tshamilemba, which is located in Lubumbashi, the second largest city of the DRC. We critically examined the district’s operational response capacity to address mental health. Methods A multimethod cross-sectional exploratory study was carried out. We conducted a documentary review (including an analysis of the routine health information system) from the health district of Tshamilemba. We further organized a household survey to which 591 residents responded and conducted 5 focus group discussions (FGDs) with 50 key stakeholders (doctors, nurses, managers, community health workers and leaders, health care users). The demand for mental health care was analyzed through the assessment of the burden of mental health problems and care-seeking behaviors. The burden of mental disorders was assessed by calculating a morbidity indicator (proportion of mental health cases) and through a qualitative analysis of the psychosocial consequences as perceived by the participants. Care-seeking behavior was analyzed by calculating health service utilization indicators and more specifically the relative frequency of mental health complaints in primary health care centers, and by analyzing FGDs participants’ reports. The mental health care supply available was described by using the qualitative analysis of the declarations of the participants (providers and users of care) to the FGDs and by analyzing the package of care available in the primary health care centers. Finally, the district’s operational response capacity was assessed by making an inventory of all available resources and by analyzing qualitative data provided by health providers and managers regarding the district’ capacity to address mental health conditions. Results Analysis of technical documents indicated that the burden of mental health problems is a major public problem in Lubumbashi. However, the proportion of mental health cases among the general patient population seen in the outpatient curative consultations in the Tshamilemba district remains very low, at an estimated 5.3%. The interviews not only pointed to a clear demand for mental health care but also indicated that there is currently hardly any offer of care available in the district. There are no dedicated psychiatric beds, nor is there a psychiatrist or psychologist available. Participants in the FGDs stated that in this context, the main source of care for people remains traditional medicine. Conclusion Our findings show a clear demand for mental health care and a lack of formal mental health care supply in the Tshamilemba district. Moreover, this district lacks adequate operational capacity to meet the mental health needs of the population. Traditional African medicine is currently the main source of mental health care in this health district. Identifying concrete priority mental health actions to address this gap, by making evidence-based mental care available, is therefore of great relevance.