Abstract: To assess the hospital prevalence of asymptomatic primary biliary cirrhosis (PBC), routine determination of serum alkaline phosphatase (AP), liver function tests (albumin, bilirubin, prothrombin time) and serum liver biochemistry (aminotransferases, gamma-glutamyltranspeptidase) were performed in 4468 consecutive in-patients (2332 men, 2136 women; mean age 57 years, range 16–94 years) admitted to our medical department from April 1991 to May 1995. In patients with an increase of serum AP levels, antimitochondrial antibody (AMA) testing, ultrasonography or CT scan, HIDA biliary scintiscan, bone scintiscan and endoscopic retrograde cholangio-pancreatography (ERCP) were performed to exclude any disorders other than PBC. Fourteen out of the 4468 patients (0.3%) showed an asymptomatic increase of AP levels (i.e., detected by chance at the entry and not earlier investigated). In 12 of 14 cases the increase of AP was not related to PBC. Asymptomatic PBC was found in 2 of 4468 patients (0.04%). When only the “risk group” (women over 40 years) is considered, the prevalence rate increases to 0.12% (2/1644 women). Our data, while not assessing the true prevalence of asymptomatic PBC in the general population, suggest that symptomless PBC is much more common than has been thus far supposed.