Background: Anti liver kidney microsome antibodies (LKM-1) have been recently incorporated to the study and classification of chronic autoimmune hepatitis (HC-A1). The presence of anti LKM-1 antibodies and essential cryoglobulinemia is frequent in virus C associated chronic hepatitis (HC-VC). Aim: To study the frequency of anti LKM-1 antibodies and cryoglobulin levels in patients with HC-AI, HC-VC and cryptogenic cirrhosis. Patients and methods: Forty two patients were studied. Nineteen adult women with classic HC-AI with positive antinuclear or anti smooth muscle antibodies. Five patients of less than 20 years old with HC-AI and negative antinuclear and anti smooth muscle antibodies. Ten adult women with cryptogenic cirrhosis, 4 women and 4 men with HC-VC. Serum samples were obtained at 37°C. Antinuclear, anti smooth muscle and anti LKM-1 antibodies were measured by indirect immunofluorescence using Hep-2 cells and rat tissue slices as substrates. Cryoglobulins were determined by the traditional method and cryocrit. Results: All studied patients were anti LKM-1 negative. All had significant circulating cryoglobulin levels. Conclusions: In this sample of patients with HC-AI or HC-VC, anti LKM-1 antibodies were not detected but all had cryoglobulinemia