Using capacitance-voltage (C-V) profiling techniques, we have investigated the effects of series resistance on the apparent carrier distribution (ACD) of quantum-well (QW) structures. It is observed that the full-width at half maximum and the peak height of the ACD change irregularly as the series resistance of the single QW perturbs the C-V measurements. It is also observed that the ACD peaks of the inner QWs in multiple QW structures are more perturbed than those of the outer QWs.