In this study we retrospectively assessed the prevalence of impaired liver function in all 49 patients suffering from Mediterranean Spotted Fever (MSF) consecutively admitted to our department over the last four years. The main parameters of liver function and ultrasound of upper abdomen were performed at entry and at the end of treatment. At admission mean values of transaminases were above the normal limits and significantly higher when compared to mean serum levels at recovery. 55% and 51% of patients had serum values of GOT and GPT, respectively, above the normal limits versus 1% and 2% at the end of treatment. Mean serum values of alkaline phosphatase (AP) were within the normal limits at entry in hospital, but 22 of them had serum values above the normal limits. The same proportion was seen for gamma glutamiltranspeptidase values. Eighteen patients (36.7%) had both transaminases and AP above the normal limits. There were no significant differences among serum values of albumin, bilirubin and gamma globulin before and after therapy. Platelet count, on the contrary, was significantly reduced at admission (p < 0.0001). At ultrasound half of the patients showed hepatomegaly with a hepatitis-like pattern and 39% of patients had splenomegaly. In conclusion, this study confirms previous data from the literature showing a high frequency of liver impairment during the course of MSF, which is usually mild-moderate. In a few cases, however, the increase of transaminases could be serious and the recovery delayed, but never, in our experience, has there been progression toward chronic liver disease.