The Vehicle Routing Problem with Time Windows (VRPTW) deals with the determination of the trips of a homogeneous fleet of capacitated vehicles based at a central depot to deliver a set of customers, while complying delivery time intervals imposed by these latter. The MultiTrip VRP with Time Windows (MTVRPTW) goes one step further by allowing vehicles to perform not one but a sequence of trips, called a journey, under a maximum overall shift length constraint. Moreover, the time to load a vehicle is service-dependent, i.e. proportional to the total service time of the subsequent trip. Hence, the MTVRPTW consists in finding a set of back-to-depot delivery trips and assigning them to vehicles so that the total travelled distance is minimized and : Ieach customer is visited exactly once and service starts within the associated time window ; Ivehicle capacity is respected ; Itrips assigned to one vehicle do not overlap in time and do not exceed a maximum duration.