We present two cases of primary malignant lymphoma of the liver, a very unusual localization of primary malignant lymphoma since only 31 similar cases were reported in the literature. The main symptoms included: hepatomegaly, fever, slight cholestasis and non specific alteration of the liver appearance on ultrasonography or computed tomodensitometry examination. Diagnosis was established in both cases by histopathological demonstration of infiltration by large lymphoid cells. Immunophenotyping in one case confirmed a B cell phenotype. Primary malignant lymphomas of the liver are high-grade malignant large-cell tumours and the immunophenotype, when known, is of the B type. The prognosis of these tumours is not well known due to their extreme rarity. They appear to be highly chemosensitive and cure may be obtained in the long-term in some cases. These data justify careful histological assessment in all cases of hepatomegaly of a tumoral nature.