Abstract: One case of chronic lymphocytic leukemia was studied by the use multiple immunological markers,cytochemically and morphologically.The studies showed that the cells were T-cell in origin,showing a peculiar phenotype:E⁺ T1⁺ T11⁺ T4^- I8^- Ia⁺.The relationship between the multiparameter studies and the clinical features in the subclassification of T-cells has been discussed and the literature concerning T-CLL reviewed.