We compared the expression of the BCL-2 oncoprotein (p26) on B cells from 24 patients with splenic lymphoma with circulating villous lymphocytes (SLVL) with that observed on normal, mature B lymphocytes and on neoplastic B cells from 91 patients with other chronic B-cell malignancies. SLVL B cells showed levels of p26 intermediate between those found on normal B lymphocytes and on neoplastic B cells from patients with other chronic B-cell lymphoproliferative disorders.