Results of laboratory tests ordered during a primary care encounter may reveal findings of abnormal liver function tests, including elevated liver enzymes, hyperbilirubinemia, hypoalbuminemia or abnormal coagulation tests. The object of this study was to describe the spectrum of these liver function test (LFT) abnormalities in primary care. Results of all laboratory tests ordered during 10 months in an urban primary care clinic were retrospectively reviewed and the medical charts of patients with abnormal LFTs were studied. In 217/1088 (20%) of the tests at least 1 LFT abnormality was found in 156 patients. New diagnoses were made in 104 patients. The main diagnostic groups were: non-alcoholic fatty liver changes, Gilbert's disease, acute infectious hepatitis, alcoholic liver disease and cirrhosis and hepatotoxic drug injury. In 60 patients the physician classified the abnormality as negligible and not associated with significant disease. However, an abnormal test that had been ordered for evaluation of a specific complaint, was indeed likely to represent significant disease (X2 = 29.5, p < 0.001). We conclude that finding abnormalities in liver function tests is common in the primary care clinic but does not often indicate significant liver disease.