Thirty-seven chronic hepatitis C patients with virological relapse (VR) after previous interferon-alpha (IFN) or IFN/ribavirin (Riba) therapy, were re-treated. Patients were randomized for either IFN/Riba and amantadine (Ama) including a 2-week initial high IFN induction course (18 MU IFN daily) (group A) or the same 2-week IFN induction course combined with Riba/Ama, followed by Riba/Ama without IFN (group B). Treatment duration for both groups was 24 weeks with a 24-week follow-up thereafter. The inclusion in group B was prematurely stopped because all patients (n = 10) relapsed within 2 weeks after stopping IFN. Therefore, all subsequent patients were included in group A (n = 27). In group A, 44% achieved a sustained virological response (SVR) and 29% of the patients with an end-of-treatment virological response had a VR again. Of all pretreatment characteristics, only genotype non-1 patients had a significantly higher chance of achieving SVR (P < 0.001). Of the characteristics during treatment only a negative hepatitis C virus (HCV)-RNA test result in transcription-mediated amplification (TMA) at week 6 had a high predictive value for SVR, 80% in all patients and 92% in genotype non-1 patients. In conclusion, hepatitis C patients with a VR to previous antiviral treatment can be successfully re-treated with IFN induction combined with Riba/Ama for only 6 months, when they have genotype non-1 and a negative HCV-RNA test result in TMA 6 weeks after the start of therapy. Riba/Ama combination therapy without IFN does not prevent VR after 2 weeks high IFN induction.