The effect of finite bandwidth of quantizers in continuous-time (CT) delta-sigma modulators (DSMs) is studied. It is shown that the finite quantizer-bandwidth in CTDSMs degrades the performance much more severely than it does in their discrete-time counterparts. It is demonstrated that CTDSMs with excess loop delay (ELD) compensation schemes require an even higher quantizer-bandwidth compared to ELD-free CTDSMs. Furthermore, it is shown that the required quantizer-bandwidth increases as the order and the out-of-band gain increases. Detailed mathematical analyses and simulation results are provided to show the effect of the finite quantizer-bandwidth.