Sjögren syndrome (SS) is a chronic autoimmune disorder characterized by lymphocytic infiltration of exocrine glands. Its correlation with B-cell-type lymphoma is justly documented. We introduce a patient with SS complicated with hairy-cell leukemia (HCL). A 51-year-old female patient, who was diagnosed with primary SS since 12 years ago, was admitted to the hospital because of intractable vomiting and abdominal discomfort due to huge splenomegaly. The blood count showed anemia, thrombopenia, and severe leukocytosis. Bone marrow biopsy and flow-cytometric analysis was diagnostic for HCL. She underwent chemotherapy and splenectomy because of symptomatic splenomegaly. Previous studies and available literature declare a close link between B-cell neoplasia and autoimmune diseases. Also, the evidences lead to the supposition that SS and other autoimmune disorders may form part of a spectrum of lymphoproliferative diseases which share common origins with clonal neoplastic B-cell proliferation.