Process and plant for producing a refuse derived solid fuel (RDSF), including a first component having a dry fraction of a solid urban waste (MSW) in a shredded form and at least one second component in a shredded form selected from an elastomeric material and a thermoplastic material, or mixtures thereof, wherein the dry fraction of the MSW, the elastomeric polymer material and/or the thermoplastic polymer material are stored in separate containers and when required are metered and fed in subsequent layers onto a continuous conveyor which discharges into a temporary accumulating container, for example, the box body of a motor vehicle, intended to directly feed the combustion plant wherein the RDSF is burned. In this way, there is no need to premix the various fractions of the RDSF during the production stage and to maintain the resulting mixture constantly stirred in order to prevent compaction and/or separation of fractions. In fact, mixing between the various fractions only takes place at the end of the production process when the RDSF is placed in the temporary accumulation container which feeds the combustion plant.