The aim of this prospective study was to analyze the incidence of serious infections and changes in immunological markers after liver transplantation (LT) in a cohort of patients with hepatitis C virus (HCV). This study included 34 patients who had LT, 20 patients with HCV etiology (HCV group), and 14 patients with alcoholic etiology (non-HCV group). Patients with HCV were more likely to have severe infections (80%) in comparison with patients in the non-HCV group (42%) (P=0.05). The HCV group had a 3-fold greater likelihood of early severe bacterial infections than the non-HCV group. At 1 week post LT, the HCV group showed higher values of CD19+ B cells/microL than the non-HCV group (P<0.05). At weeks 4 and 12 post LT, the HCV group had lower values of CD19+ B cells/microL (P<0.05). Our data suggest that HCV recurrence after LT was associated with a high incidence of early severe infections and immunological alterations, which may be related to this increased risk.