This chapter discusses the temperature dependence of electrical parameter variations in MOSFET devices. The parameters investigated for MOSFETs include threshold voltage, mobility, drain current, time delay, strong inversion leakage, subthreshold leakage, and chip availability. The magnitude of the leakage current depends on how well the transfer device channel can be turned off during standby, which in turn depends on the gate voltage and threshold voltage of the device. The delineation factor quantifying the temperature dependence is larger for cells driving loads dominated by temperature-dependent junction capacitances than for temperature-independent capacitive loads. The model can be extended to calculate the delay time for a CMOS ring oscillator, which consists of either seventeen or thirty-seven stages of directly coupled inverters. The signal loss due to leakage current is proportional to time. To prevent the signal from falling the magnitude needed for sensing, the cells in a dynamic random access memory need to be refreshed periodically.