In this paper, a testing technique based on supply current verifying is presented, for fault detection of analog circuits containing CMOS operational amplifiers. This testing technique is employed and developed to maximize the fault coverage of the circuit under test (CUT) using transient and frequency responses of the supply current. This testing method is based on the over-sighting of the quiescent supply current (Iddq) of the CMOS operational amplifier operating in its quiescent mode and the supply current of the CMOS operational amplifier used as a Sallen-Key band pass filter in the AC and transient operating domains. The faults investigated in our study are of bridging and open circuit types that occur at the CMOS transistor level. The Pspice software was used for the CUT simulation by applying Monte-Carlo analysis in faulty and fault free conditions. Test parameters are extracted and selected to be used as input features of our classifier.