Extensive simulations indicate that in most but not all cases the single- and two-phase models predict similar dynamic behavior of a reverse-flow reactor, when catalyst pellet multiplicity does not occur at any point in the reactor. Differences in the predictions are found in some cases close to the dynamic bifurcation loci of a cooled RFR, or in others when the qualitative dynamic behavior is very sensitive to the value of the parameters, such as close to a transition to chaotic behavior. The two models can lead to rather different predictions of the dynamic features when there are large differences between the feed and coolant temperatures.