Diffuse large B-cell lymphoma (DLBCL) is the most common aggressive B-cell non-Hodgkin�s lymphoma. Oxidative stress, defined as an imbalance between the levels of pro-oxidants and the antioxidant defense, is involved in lymphomagenesis via chronic inflammation and is associated with a decrease in circulating levels of high-density lipoprotein (HDL) cholesterol. We evaluated oxidative stress levels in DLBCL patients by FORT (Free Oxygen Radicals Testing) and FORD assays (Free Oxygen Radical Defense), and investigated the relationship between oxidative stress markers and HDL-cholesterol levels. Our results suggest that oxidative stress and decreased levels of HDL-cholesterol might play a role in DLBCL pathogenesis via chronic inflammation.