Existing kinetic data on the pearlite reaction are reevaluated in terms of recently derived rate laws. It is found that the nucleation rate varies more rapidly with temperature than previously supposed, and that for eutectoid steels below about 660°C the nucleation rate is high enough for the transformation rate to become independent of the nucleation rate. The time dependence of the nucleation rate obtained from kinetic data is consistent with that observed by metallographic methods. An analysis of the pearlite reaction in the presence of carbide particles supports the two-stage nucleation concept, as well as a transient in one of the stages of nucleation.