Acute hepatitis C virus infection becomes chronic in 50-80% of patients; in recent years a number of studies on acute hepatitis C have shown that interferon treatment can solve more than 80% of cases. In this study we evaluated all cases of acute hepatitis C referred to our unit from 1998 to 2005 to study the epidemiological and clinical features and the efficacy of interferon therapy during the course of the disease. Forty-three patients (28 males, 15 females) were monitored: 22 were drug-addicts, 6 patients referred from recent surgery, in 3 cases a percutaneous exposure was described, 2 patients had had a colonoscopy, 4 were partners of subjects with chronic hepatitis C and in the remaining cases the transmission route was uncertain. All subjects were symptomatic, jaundice was evident in 20 out of 43 patients and in all cases hepatic protein synthesis was unaltered. Of the 21 patients who consented to interferon therapy, in 19 cases a sustained virological response was achieved while in 2 cases the follow-up period was too short for evaluation. Four of the 22 non-treated patients had a spontaneous resolution of the infection, in 13 cases the infection became chronic, and in 4 cases the follow-up was too short for an analysis. In our study all patients were young, in 58% of subjects a parenteral exposure was described and most patients were drug-addicts. All the treated patients obtained a sustained response, while in the majority of non-treated cases the infection became chronic.