We present for the first time in the German dermatologic literature results of systematic investigations on the relationship between scleroderma, antimitochondrial autoantibodies and primary biliary cirrhosis (PBC). 40 patients with different clinical pictures of systemic and localized scleroderma were examined. By means of indirect immunofluorescence technique, in the sera of 5 cases (12.5%) antimitochondrial autoantibodies (AMA) could be detected. The target autoantigens for the AMA were identified as pyruvate dehydrogenase, branched-chain alpha-ketoacid dehydrogenase, alpha-ketoglutarate dehydrogenase, protein x and pyruvate dehydrogenase E-1 alpha in all 5 cases, PBC was confirmed by means a liver biopsy and endoscopic retrograde cholangioscopy. Considering the occurrence in the normal population, the prevalence of the PBC in our scleroderma collective was 8.3 x 10(2) to 2.5 x 10(3) x higher. In respect to the clinical picture of the scleroderma, we found a M2-antibody-positive PBC in 2 woman with CREST syndrome and in 1 woman with a acral-type of the progressive systemic scleroderma. CREST syndrome and coexistently M2-antibodies in the serum are a risk constellation for the development of PBC. In 2 female patients older than 50 years we observed the coincidence of disseminated plaque-like localized scleroderma and a M2-antibody-positive PBC. In our opinion this latter constellation is a specific entity. The administration of ursodeoxycholic acid (daily 15 mg/kg BW) in 3 cases led not only to dramatic improvement of the clinical symptoms of PBC as expected, but also to pronounced improvement of skin lesions of 2 patients with disseminated circumscribed and 1 patient with progressive systemic sclerosis. Thus PBC should be searched for in patients with scleroderma, especially those with CREST syndrome or widespread localized disease; it may have practical therapeutic value as well as immunological significance.