Rituximab is the first antibody-based therapy approved in cancer. The role of this treatment for non-Hodgkin's lymphoma has evolved significantly since its introduction. We aimed to systematically review the literature on rituximab in non-Hodgkin's lymphoma and provide consensus guidelines as to the rational use of this agent. Validated methodology from the Cancer Care Ontario Program in Evidence-Based Care was applied. A comprehensive literature search was completed by reviewers from the Hematology Disease Site Group of Cancer Care Ontario. Data were abstracted from randomized controlled trials of rituximab-containing regimens for patients with non-Hodgkin's lymphoma. Twenty-three randomized controlled trials (RCTs) of rituximab-based therapy were analyzed. Consistent and clinically important benefits in progression-free and overall survival and were seen in the following settings: (1) addition of rituximab to combination chemotherapy for initial treatment of diffuse large B-cell lymphoma and other aggressive B-cell lymphomas; (2) addition of rituximab to combination chemotherapy for initial and subsequent treatment of follicular lymphoma and other indolent B-cell lymphomas; and (3) use of rituximab alone as extended maintenance therapy in patients with indolent B-cell lymphomas who have responded to initial treatment. The consensus opinion of the Hematology Disease Site Group is that rituximab is recommended for these indications.