The author reports about five patients suffering from a primary fibrotic stenosis of the biliary system. All patients were assigned into hospital with a painless jaundice. In all cases a diagnosis was secured histologically. Four patients had a stenosis of the biliary system and a hepatico-jejunostomy as Y-anastomosis was possible to be applied. In one case both Ductus hepatici were taken ill symmetrically. A biliodigestive anastomosis was not practicable. After having widened the narrow intra-hepatitic biliary system, the stenosis appeared once more. It could not be found that the total intra- and extra-hepatic biliary system had fallen ill symmetrically. The cause of the illness is still uncertain. Based on clinical and histological findings an inflammatory process is not probable. The pathological anatomical findings were marked by a network-like filament of collagene without inflammation.