The Sezary's syndrome is a lymphoproliferative disorder from the group of chronical lymphocytic leukaemia originated from the T-cell lineage. Authors are presenting the patient with Sezary's syndrome for the first time ever diagnosed in the Institute of Haematology. The patient, 58 years old got ill in summer 1989. with the symptoms of strong itch and erythematous papullas over the sin. In April 1990. he came to the Institute of Hematology where he was diagnosed as a Sezary's syndrome case on the evidence of generalized erythrodermia, identification of lymphocytes with cerebriform nucleus in peripheral blood and membrane-marker analysis that showed aberant post-thymic proliferation of T-lymphocytes in bone marrow. The patient wastreated with a polychemiotherapy and with "electron beam" therapy with temporary improvement, but died in January 1991 with sepsis and a hepathorenal syndrome.