Autoimmune phenomena in lymphoid malignancies are often observed. However, clinical manifestations such as a secondary antiphospholipid syndrome in the presence of antiphospholipid antibodies are rarely reported. Furthermore, in the few cases of lymphomas so far reported with thrombosis associated with elevated antiphospholipid antibodies, the anti-beta2-glycoprotein-I antibodies have not been studied. We report on two cases of arterial thrombosis occuring in patients with B-cell lymphoma who presented with positive anticardiolipin and anti-beta2-glycoprotein-I antibodies. Our observation suggests that patients with non-Hodgkin's lymphoma and both anticardiolipin and anti-beta2-glycoprotein-I antibodies may be, similar to lupus patients, at considerable risk towards thrombosis, especially towards arterial thrombosis.