Because there is a lack of data on the treatment outcome of patients who carry hepatitis C virus (HCV) genotype 6, we conducted a prospective study, to compare the effect of interferon and ribavirin therapy in HCV genotypes 1 and 6, of patients with seropositive anti-HCV, persistently elevated alanine transaminase levels, and detectable HCV RNA. Patients were treated with subcutaneous recombinant interferon alpha-2b and ribavirin for 12 months. Of 40 patients, 16 had genotype 6, and 24 had genotype 1. An end-of-treatment response was detected in 12 (75%) patients with genotype 6 and in 10 (41.6%) patients with genotype 1 (P=.05). A sustained virological response (SVR) was present in 10 (62.5%) patients with genotype 6 and in 7 (29.2%) patients with genotype 1 (P=.04). Genotype 6 has a better response than genotype 1 and is associated with a higher SVR.