Non-Hodgkin lymphomas are lymphoid malignant neoplasms with diverse biological and clinical behavior. Patients typically present with persistent painless lymphadenopathy, but some patients may present with constitutional symptoms or with involvement of organs other than the lymphoid and hematopoietic system. An accurate diagnosis, careful staging of the disease, and identification of adverse prognostic factors form the basis of treatment selection. Patients commonly receive chemoimmunotherapy as initial treatment, and radiation therapy may be added if patients have early-stage disease. Most patients respond well to treatment, but relapses are frequent and additional therapies including stem cell transplant are often needed. Because many subtypes of lymphoma remain incurable with current management strategies, clinical trials are in progress to identify novel therapies with promising activity in this disease.