Glucose intolerance often occurs in liver cirrhosis; therefore a long-term control of plasma glucose levels appears to be important. For this purpose glycated hemoglobin A (HbA1c) determination is proposed as a suitable method, while no data are available on fructosamine test. In 98 cirrhotic patients serum fructosamine and HbA1c levels were compared with those of normal controls and among cirrhotic patients grouped in non glucose-intolerant and with non insulin-dependent (NIDDM) or insulin-dependent diabetes mellitus (IDDM). The mean HbA1c values of cirrhotic patients with normal glycemic control were significantly lower than normal, and only a few IDDM and NIDDM cirrhotic patients showed high values of HbA1c, indicating that HbA1c is often underestimated in these patients. On the contrary, serum fructosamine levels were on the average higher than normal in nondiabetic patients, but they were significantly higher in IDDM and NIDDM patients than in nondiabetics, and the 72% of NIDDM and 85% of IDDM patients had fructosamine levels higher than the upper normal value. In conclusion, in diabetic patients with liver cirrhosis fructosamine seems to be a more suitable test than HbA1c for monitoring blood glucose levels.