Rituximab has been demonstrated to sensitize drug-resistant NHL cells to the cytotoxic actions of several chemotherapy agents by enhancing sensitivity of tumor cells to chemotherapy-induced apoptosis. Gemcitabine, a nucleoside analog that is used in several other malignancies, has shown very promising activity in patients with refractory Hodgkin's disease and low-grade NHL. The combination of rituximab and gemcitabine may have synergistic cytotoxic action in patients with relapsed or refractory DLBCL and possibly lead to improved response rates and demonstrable clinical benefit.