In this paper, a comparison between MOSFET based and CNTFET based Analog to Digital Converter (ADC) performance is investigated with SPICE simulations using similar process technologies. The results suggest that CNTFET based ADC can result in lower power consumptions than its MOSFET counter-part with low supply voltages. Non-linearity in CNTFET based ADC is smaller in comparison to MOSFET based ADC for smaller resolution. As the resolution increases there is no big change in Integral Non-Linearity (INL) and Differential Non-Linearity (DNL) and are almost similar values for both MOSFET and CNTFET based ADCs.