This study presents the first experimental data for the impact of hot-carrier degradtion on the performance of CMOS folded-cascode op-amps. A folded-cascode op-amp which has an NMOS input pair has been designed and fabricated using a 0.8.mu.m single-poly, double-metal CMOS process. After high voltage stress, the degradtion of perfomrance parameters such as open-metal CMOS process. After high voltage stress, the degradation of performance parameters such as open-loop voltage gain, unity-gain frequency and phase margin has been analized and physically explaniend in terms of hot carrier degradation.