The invention relates to a self-propelled civil engineering machine, in particular a road-milling machine, a road recycler, or a road stabilizer, having a frame carried by a set of running gear, a working unit for performing work required for the civil engineering operation, and in particular a working drum, and a drive unit carried by the frame of the machine, to drive the working drum. A power transmitter is used to transmit the driving power from the drive unit to the working unit. The drive unit of the self-propelled civil engineering machine has a first and a second drive engine, the power transmitter being so designed that the driving powers coming from the first and the second drive engines can be transmitted to the working unit together. With the design of drive according to the invention, a particularly space-saving construction is obtained for the drive and this allows the power of the drive unit to be increased without having to exceed the present width for transport of the self-propelled civil engineering machine.