The authors wanted to determine whether adding interferon-alpha (IFN-alpha) to chemotherapy regimens, in either induction or maintenance settings, provides additional survival benefits in follicular non-Hodgkin's lymphoma (NHL). A meta-analysis was performed based on published data from randomized controlled clinical trials involving nine separate study populations. Patients receiving IFN-alpha (in either induction or maintenance therapy) had significantly increased 5-year and progression-free survival rates at 3 and 5 years compared with concurrent controls. The advantages of IFN-alpha therapy were most marked in studies using anthracycline-containing induction chemotherapy; in these studies, patients who received IFN-alpha had approximately 20% increased progression-free survival rates compared with controls and a lesser survival advantage. The available literature did not allow a determination of the relative benefit of IFN-alpha in induction or maintenance treatments for NHL or a determination of the optimum duration of IFN-alpha treatment. Although questions remain about its optimal use. IFN-alpha appears to prolong survival time in patients with follicular NHL.