Background: Rituximab, a chimeric mouse/human monoclonal antibody targeting the pan-B-cell antigenic marker CD20, was the first monoclonal antibody licensed for use in the treatment of cancer. Objective: This review focuses on the impact of rituximab in the treatment of patients with B-cell non-Hodgkin lymphoma (NHL). Methods: Three key areas related to the use of rituximab in B-cell NHL are discussed: mechanism of action, clinical efficacy in both indolent and aggressive disease, and safety of its use as both monotherapy and in combination with chemotherapy. Results/conclusions: Rituximab has demonstrated significant clinical efficacy in the treatment of NHL, particularly in combination with chemotherapy, and its use has revolutionized the treatment of both indolent and aggressive B-cell NHL over the past decade. Furthermore, consistent toxicity data have been obtained with a safe and tolerable profile in most patients.