Histological evidence of primary biliary cirrhosis (PBC) recurring after orthotopic liver transplantation (OLT) was looked for in a 'blinded' study of 353 biopsies from 188 patients, 12-100 months post-transplant. Biopsies (172) were obtained from 83 patients transplanted for PBC and 181 biopsies from 105 patients with other liver diseases. Sixteen biopsies from 13 PBC patients (16%) had features suggestive of recurrent disease. The main diagnostic findings were: mononuclear portal inflammatory infiltration (n = 16), portal lymphoid aggregates (n = 14), portal epithelioid granulomas (n = 14) and bile duct damage (n = 15). This combination of changes was not seen in any biopsy from the non-PBC group. Additional features supporting a diagnosis of recurrent disease were ductopenia (n = 7), bile ductular proliferation (n = 7), portal fibrosis (n = 6) and copper deposition (n = 5). Thirteen biopsies from 12 patients were classified as stage I or II histologically. The other patient developed progressive damage in three serial biopsies resulting in an early micronodular cirrhosis, 5 years post-transplant. These observations provide further evidence that PBC recurs after OLT. More studies are required to determine the natural history and clinical significance of the predominantly early histological changes documented so far.