In data acquisition applications where the signals being digitized are produced in a time-division multiplexed system, the required dynamic performance of the analog-to-digital converter (ADC) is no longer bound by the conditions set forth in the Sampling Theorem. This results from the introduction of very high frequency information by the multiplexing process which, while not necessarily containing information of interest, must be processed by the input circuitry of the ADC. In this situation, signal bandwidths and slew rates can greatly exceed those produced in a Nyquist limited system and can surpass the capability of the ADC, thus degrading overall system performance. This paper will examine two common multiplexing schemes and their impact on ADC dynamic requirements. First, we will examine a simple voltage multiplexing scheme typically found in state-ofhealth or data-logging applications and develop the necessary equations to show how the ADC dynamic requirements are affected. Then, the analysis will then be extended to a multiplexed photodiode array readout to see how this application further challenges the dynamic performance of the ADC. Finally, the issues associated with developing dynamic test methodologies for assessing ADC performance in multiplexed systems will be discussed.