Primary sclerosing cholangitis is a chronic cholestatic disease that may have an autoimmune basis. Most patients have a circulating antineutrophil cytoplasmic antibody that appears to be targeted against a 50-kD nuclear envelope protein. The clinical applications of this antibody have not yet been defined. Other autoantibodies directed against antigens, such as cathepsin G, elastase, and anticardiolipin, may also be detected in some patients. It is suggested that primary sclerosing cholangitis may have a bacterial cause. Helicobacter gene sequences have been detected in liver tissues in primary sclerosing cholangitis. The role of Helicobacter spp and other bacteria in the etiopathogenesis of primary sclerosing cholangitis remains to be determined. Primary sclerosing cholangitis may overlap with autoimmune hepatitis in some cases, although the real prevalence of this association remains to be determined. Many prognostic models have been created, but they lack cross-validation, and their clinical usefulness remains limited. Endoscopic retrograde cholangiography remains the gold standard for diagnosis, but magnetic resonance imaging may be a viable alternative in many cases. Clinical trials with cladibrine, pentoxifylline, and budesonide have failed to demonstrate benefits. Orthotopic liver transplantation remains the only effective treatment.