Sjögren's syndrome (SS) is an autoimmune disease characterized by a lymphocytic infiltration of the salivary and lacrimal glands leading to a progressive destruction of these glands due to the production of autoantibodies. This disorder is either isolated (primary SS) or associated with other systemic diseases (secondary SS). The occurrence of B-cell non-Hodgkin's lymphoma (NHL) represents the major complication in the evolution of SS patients. The risk of developing NHL, which is equivalent for both primary and secondary SS, was estimated to be 44 times greater than that observed in a comparable normal population. NHLs in SS patients occur preferentially in the salivary glands and in other mucosa-associated lymphoid tissues (MALT). However, it can also occur in the lymph nodes or bone marrow.