Three patients affected by T helper chronic lymphocytic leukemia were treated with low dose interferon alpha-2b (3 MU/m2 3 times weekly). The disease presented different pathologic expressions with diffuse skin lesions in one patient, a mild clinical course and a prolymphocytic variant with aggressive features, respectively, in the other two cases. A consistent response was observed within 3-6 weeks; by that time a reduction of blood and marrow lymphocytosis in the three patients and a regression of the cutaneous lesions were documented. Therefore, it should be emphasized that the use of alpha IFN, whose effectiveness on cutaneous T cell lymphomas has been already demonstrated, may represent an active agent in the treatment of leukemic T helper phenotype chronic lymphocytic proliferations.