As yet, psychoeducational practice lacks a reliable and valid set of established classifications of learning behaviors, which is an indispensable starting point for the diagnosis of a child's problems. This paper reports an epidemiologycal study in which we collected descriptive behavioral data from a fairly representative sample (N = 150) of Dutch third-grade children who show severe learning problems. These children were described by their teachers (N = 150) with respect to their behavioral responses to a set of reading and spelling tasks that are commonly used in Dutch elementary reading and spelling instruction. Cluster analyses resulted in the identification of four syndromes in elementary reading and spelling behavior. Further analyses, based both on the epidemiological data and on further data collected in additional small-scale studies, show these four syndromes to be both reliable and valid. (Contains 2 tables and 2 figures.)