The finding of epithelioid cell granulomas within liver biopsies is a not uncommon occurrence. We undertook this study to investigate the underlying conditions responsible for a diagnosis of granulomatous hepatitis in Northern Ireland during the thirteen year period 1980-1992. One hundred and sixty-three patients with hepatic granulomas were identified, accounting for 4% of all liver biopsies undertaken during the period of the study. In 145 cases (89%) a definite clinical diagnosis was established. The most common clinical diagnoses were primary biliary cirrhosis which accounted for 90 cases (55%) and sarcoidosis which accounted for 30 cases (18%). Other less common conditions associated with hepatic granulomas included tuberculosis (3 cases), Crohn's disease (3 cases), chronic active hepatitis (2 cases), drug hypersensitivity (2 cases) and extra-hepatic biliary obstruction (2 cases). Six patients were identified with a clinical diagnosis of psoriasis. Other miscellaneous conditions accounting for single examples of granulomatous inflammation were schistosomiasis, gout, Hodgkin's disease, secondary adenocarcinoma, collapse and necrosis of tumour following radiotherapy and chemotherapy, granulomatous inflammation within the wall of an abscess cavity and idiopathic cirrhosis. Only eighteen cases (11%) remained idiopathic with no definite diagnosis established after detailed investigation. The findings confirm the wide range of clinical conditions which can result in hepatic epithelioid cell granulomas. This has been emphasised in several previous major studies which are reviewed in this paper.