Over the last ten years the incidence of primary sclerosing cholangitis (PSC) presented a progressive increase, showing an association with chronic inflammatory bowel disease (IBD) in 50-70% of the cases. Nowadays, however, the prevalence of PSC is still unknown, mainly because of its difficult identification. In contrast to primary biliary cirrhosis (PBC), which is strongly associated with the presence of anti-mitochondrial antibodies (AMA) in serum, a similar reliable diagnostic marker has not yet been demonstrated in PSC. In this review we tried to investigate the controversial diagnostic aspects which may interfere with the initial assessment of PSC syndrome. Alkaline phosphatase (ALP) and endoscopic retrograde cholangiography (ERC) are actually the two cornerstones of the clinical setting, but if alone, they do not seem to provide sufficient accuracy. Furthermore, liver biopsy, perhaps more sensitive but not always specific, is generally performed too late. In our opinion, epidemiologic studies are needed in Italy and elsewhere in order to evaluate PSC prevalence. Moreover, the analysis of these results might lead to an earlier detection of the disease and, perhaps, favourably modify its natural history.