The transient heat transfer in micro and nanochannels has been investigated under the effect of dual-phase-lag heat conduction model. The velocity slip and temperature-jump boundary conditions are considered in addition to the conjugate heat transfer boundary condition. The effects of physical parameters are investigated and the corresponding value of these parameters has been proposed using the least-square fitting method. The DPL model is revisited in order to include the convective term in material derivative. Then the resulting model has been used to investigate the thermal behavior of the metal oxide semiconductor (MOS) devices.