An integrated circuit that includes a processor also has an on-chip current test circuit that indirectly measures quiescent current in the processor. A supply voltage pin of the integrated circuit receives a supply voltage from an external test unit to provide power to the processor. The on-chip test circuit measures a voltage change across the processor during a predetermined test period T when the processor is isolated from the supply voltage and the clock signal is stopped. The voltage change provides an indication of quiescent current corresponding to the processor.