Multiple gate MOSFETs (MuGFET) have gained significant attention as the scaling of the conventional MOSFET comes to an end. Of the possible architectures, the gate-all-around nanowire (NW) transistor offers the best gate control over the channel. In order to model GAA nanowire devices for channel lengths less than 10nm, while preserving a connection to the drift-diffusion framework familiar to device engineers, we have developed a quantum-corrected transport simulator that includes Quantum Drift-Diffusion (QDD) [1] and Quantum Energy Balance (QEB). This formalism is applied to the example of the NW junctionless transistor (JLT), an interesting modification to the NW-MOSFET obtained by replacing the n+-p-n+ structure by a bar of n+ region, that promises smaller variability [2]. © 2012 IEEE.