The Kiel and Lukes-Collins classifications of non-Hodgkin's lymphomas are the only classifications based on immunological concepts. Their cytological types have been confirmed by numerous immunological studies as B- and T-cell types and have been related to clinico-pathological entities. In this presentation, the cytological types of the two classifications are compared. Eleven of the 13 major types of the Lukes-Collins classification are essentially identical with the Kiel counterparts, though the terminology differs in four of the 11 types. In the two types in which discordance occurs, the relationship between the types of the two classifications are clarified. As a result, the two classifications are placed into effective alignment for understanding and translating terminological differences. Both classifications represent sound bases for morphological diagnoses and also for relating the results of the broad range of current and future immunological studies to morphology.