A new continuous semi-empiric compact model for the current transfer characteristics of surrounding gate undoped polycrystalline silicon (Poly-Si) nanowire (NW) MOSFETs is proposed. The model consists of a single equation based on the Lambert function, which contains only four parameters and is continuously valid and fully differentiable throughout weak and strong conduction regimes of operation. The model is tested on measured transfer characteristics of experimental devices. The extracted model parameters are used to generate transfer characteristics playbacks that are then compared to the measured data to validate the proposed model's adequacy for these devices. (C) 2011 Elsevier Ltd. All rights reserved.