Asymptomatic patients with raised liver enzymes are frequently encountered in clinical practice. The commonest lesion in such patients appears to be fatty liver, which may be found in those only modestly overweight. Proven treatments other than abstention from alcohol and weight loss are available for approximately 20% of asymptomatic people with abnormal liver enzymes. However, if experimental therapies are taken into account this would rise to over 50%, making an early accurate diagnosis important. Most conditions can be diagnosed non-invasively, especially in those people with markedly abnormal transaminases. The recent introduction of new non-invasive tests decreases the need for liver biopsy for diagnostic purposes, however liver biopsy retains an important role in establishing patient prognosis and response to treatment.