In the attempt to discriminate between centroblasts and immunoblasts, an analytical morphometrical procedure was adopted, considering the nuclei of a randomly selected centroblastic and immunoblastic population from non-Hodgkin's lymphomas and the nucleoli of a more restricted number of the same neoplastic population. All the size-independent shape-descriptor parameters extracted for each step of the mathematical analyses used were submitted to Hotelling's multivariate discriminant analysis that enabled us to achieve a good distinction (3% error) between centroblasts and immunoblasts when nuclear and nucleolar parameters were used together.