In a retrospective analysis the authors studied the relation between the immunologic phenotype of B-cell non-Hodgkin's lymphoma (NHL) and disease-free survival. The phenotype included immunoglobulin isotypes; B-cell maturation/differentiation antigens of clusters of differentiation CD9, CD10, CD19-24, CD37, CD38; T-lymphocyte antigens in CD5-7; HLA-DR; peanut agglutinin binding capacity; terminal deoxynucleotidyl transferase; the activation marker CD25 (interleukin-2 receptor); and the proliferation marker transferrin receptor. The phenotype and clinical data were available for 109 patients. Two patients underwent bone marrow transplantation, and 15 patients (with low or intermediate grade NHL) did not receive treatment intended to achieve complete remission. These 17 cases were excluded from the analysis. For individual markers, CD23 expression was associated with a longer actuarial disease-free survival (50% survival in CD23-positive cases was 40 months; and in CD23-negative cases, 16 months; P = 0.01). Among the total study population of 92 patients, this finding applied in particular to those with a low-grade malignancy according to the Kiel classification (P = 0.03). In high-grade NHL (Kiel classification) the absence of CD38 or presence of CD24 on tumor cells correlated with a higher degree of disease-free survival (P values 0.009 and 0.04, respectively). For a combination of five CD markers associated with stages in physiologic B-lymphocyte maturation/differentiation (CD9, CD10, CD21-23), the lowest measure of disease-free survival was observed where NHLs were at an immature stage, and the greatest extent of survival where NHLs were associated with a resting B-cell stage (P = 0.006). These statistical significances aside, the detailed immunologic phenotyping has relatively little prognostic value when compared with that of the malignancy grade assessed by conventional histopathology.