Recombinant and natural forms of interferon alpha have been shown to bring about tumor regressions in patients with low-grade non-Hodgkin's lymphoma. Complete and partial response rates in up to 50% of patients have been documented. Although these studies are encouraging, interferon alpha's role in the current management of patients with low-grade non-Hodgkin's lymphoma is not apparent. The high doses of interferon that were used in some of the recent studies were not well tolerated by these patients. Current studies using interferon in patients with low-grade non-Hodgkin's lymphomas are evaluating lower, and perhaps better tolerated doses of interferon. In addition, in vitro studies have documented additive and sometimes synergistic antitumor effects of interferon in combination with cytotoxic drugs. This approach is being extended to the clinic, and trials are now underway evaluating combinations of interferon and various cytotoxic drugs known from previous studies to be active in patients with low-grade non-Hodgkin's lymphomas. This report reviews studies using interferon alone in these patients, and discusses ongoing and proposed studies for the future use of interferon in treating this disease.