This paper discusses the impact of the short channel effects, such as channel length modulation (CLM), velocity saturation effect (VSE) and hot carrier effect (HCE), on the channel thermal noise model of short channel MOSFETs. Based on the fundamental thermal noise theory, the channel thermal noise models are derived in four different cases considering the effect of CLM only, CLM and VSE, CLM and HCE, and the combine effect of CLM, VSE and HCE. The noise reduction due to the VSE is found to be completely cancelled out by the noise increment due to the HCE for all the operating conditions. (c) 2012 Elsevier Ltd. All rights reserved.