The immunogenicity and tolerability of an adjuvanted trivalent influenza vaccine was evaluated in 20 patients with cirrhosis due to chronic HBV or HCV infections and eight healthy age matched controls. Seroconversion or a four-fold or greater increase in HI antibody titres to each antigen occurred in 75-85% of the patients and in 100% of the controls. One month after vaccination, the geometric mean antibody titres were significantly higher than baseline in both groups of vaccinees. A mild and transient erythema at the inoculation site was the only side effect for both groups. The results justify the use of an adjuvanted influenza vaccine, given as single-dose, in patients with advanced liver disease.