Untreated patients with low-grade non-Hodgkin's lymphoma (NHL) demonstrate a natural course of the disease differing from between a few months and decades. Prognostic factors to assess survival probability have recently been defined. Cure seems possible in the rare localized stages by irradiation. In advanced stages watchful waiting is still indicated. There is not enough evidence at present that aggressive induction prolongs survival. However, approaches such as autologous bone marrow transplantation or peripheral stem cell transfusion are currently being investigated in clinical trials but so far information is still lacking on the quality of life and the incidence of late complications such as the development of a second malignancy. Interferon alpha may have an influence on prolonging the duration of remission in follicular lymphoma. The poor prognosis of low-grade T-cell NHL and centrocytic lymphoma (CC) stresses the necessity for new therapeutic modalities. Purine analogues show efficacy in some subtypes of NHL and further investigations are warranted.