A device for retaining drained fluids for a propulsive assembly includes a cavity for storing the drained fluids and two walls mounted at the opening of said cavity. The cavity has a fluid storage volume V1 when the device is in a substantially vertical position, and each wall is configured such as to define a fluid storage volume (V2 and V3 respectively) in the cavity when the device is in a substantially horizontal position, each of the volumes V2 and V3 being at least equal to the volume V1.