It has been well known that in a long‐channel MOSFET, the experimental value of the threshold voltage obtained by the square‐root extrapolation method in the saturation region agrees well with the theoretical criterion. In a short‐channel MOSFET, the so‐determined threshold voltage depends on the drain voltage because of the drain current dependence on the drain voltageVDS. In this letter, a new method to determine the threshold voltage forVDS=0 V will be discussed.