La prison overcrowding is a recurrent problem faced by many prisons in RD Congo and many other states around the world. It creates inhumane living conditions for detainees by creating promiscuity between them and facilitating the spread of diseases in prison. In addition, it creates a poor working environment for prison services1. Hence the need to reflect, in the context of this article, on the mechanisms to be put in place to curb this phenomenon. We first examine the causes of this overcrowding and then its impact both on the rights of persons deprived of liberty and on the work of prison staff. The conclusion is that the abnormally long duration of pre-trial detention is the main cause of prison overcrowding in RD Congo and, in order to deal with this scourge, it is imperative to regulate prison entries and facilitate early exits or prison adjustments.