Medicines are one of the pillars of the healthcare system. Equitable access to medicines must be ensured by a supply system that guarantees their availability, quality, safety, efficacy and cost-effectiveness. This is the background to this study, which aims to contribute to improving the availability of essential generic medicines needed for good patient care in the three Health Zones of the town of Mbandaka in the Democratic Republic of Congo. The study was conducted using a retrospective approach covering the period from January 2013 to June 2015. Its objectives were to describe the organisation of the supply system for essential generic medicines in the health zones studied and the human resources in the supply chain in each health zone studied, but also to identify the problems common to the health zones studied in relation to supply chain management. The study showed that not all public health structures in the city of Mbandaka have an efficient supply system guaranteeing availability and quality.