ABSTRACT The work proposes a physically accurate quasi-ballistic drain current model valid for Double Gate (DG) MOSFETs in the nanoscale regime. The proposed quasi-ballistic model considers the carrier scattering physics and includes both ballistic and diffusive transport. Based on the concepts of scattering theory, a semi-empirical approach is used to determine the diffusive carrier scattering at the critical channel length as a function of drain bias. A generalised three region scale length model is applied to the proposed device structure with arbitrary dielectric constants and oxide thicknesses to examine the device channel length scaling limits. The significance of Eigen values and the scale length equations applicable for the proposed device structure is discussed. The drain current model essentially captures the key signature effect observed in rigorously scaled short channel devices. Further, the proposed quasi-ballistic model demonstrates its physical aptness and optimal accuracy when compared with other similar recent works. The model results obtained are verified using numerical simulations and are found to exhibit excellent continuity in all regions of the device operation.