The simultaneous occurrence of a small B-cell lymphocytic neoplasm and a T-cell lymphoma in the same lymph node biopsy specimen is documented in two patients. The biopsy from the first patient, who had a 5-year history of chronic lymphocytic leukemia, showed evidence of a small B-cell lymphocytic neoplasm coexisting with a large-cell lymphoma of T-cell phenotype. The lymph node biopsy specimen from the second patient showed features of small lymphocytic lymphoma of B-cell phenotype, coexisting with a small-cell pleomorphic lymphoma of T-cell phenotype. The lymph node specimens from both patients met strict criteria for composite lymphomas. The clinical and morphologic findings in the first patient are those of "Richter's transformation" of chronic lymphocytic leukemia. The lymph node biopsy specimens from these two patients demonstrate that small B-cell lymphocytic neoplasms may coexist with T-cell lymphomas.