This review focused on the main aspects of aggressive non-Hodgkin's lymphomas (NHL) in the population aged 65 years or older. In parallel with the increase of the elderly in the populations of western countries, there has been a steady increase in incidence and mortality rates of NHL in industrialised countries. This pattern has been particularly marked among the older segment of the population. New advances in cytogenetic and molecular genetics have favoured a better definition of lymphoid malignancies, but it is still unclear whether a biologically different disease may develop more frequently in elderly patients. Up to the mid-1990s, elderly patients with NHL were often excluded from randomized trials because of their age and because of comorbidity. Presently, barriers to the enrollment of elderly cancer patients in clinical trials are less stringent, and elderly patients may now take benefit from advances in our knowledge as younger patients do.