Over 200 cases of non-Hodgkin's lymphoma were typed for HLA-A, B, C and DR antigens, and typing was correlated with the morphologic diagnosis according to the Lukes-Collins classification system of non-Hodgkin's lymphomas. Three major racial groups were represented: Caucasoids, Mexican-Americans and Negroids. Significant associations were observed between HLA-AW33 and Caucasoid B-cell lymphomas, and for HLA AW24, HLA-B37 and HLA-B40 and B cell lymphomas in Negroids. No significant correlations were found within the Mexican-American patient population. The number of T cell lymphomas was insufficient to draw any conclusions. The DR antigens were not significantly associated with any of the diagnostic subgroups.