We investigated stable cirrhotic patients for muscle glycogen content. Muscle biopsy samples were taken of 14 patients after overnight fasting. Electron microscopy showed normal intracellular distribution of glycogen (n = 8). Muscle glycogen concentration was 16.5 +/- 7.1 gm/kg wet muscle weight (normal range, 10 to 20 gm/kg). Basal, early postabsorptive, exercise-induced and insulin-induced respiratory quotients as well as insulin sensitivity (euglycemic clamp technique, 7.2 pmol insulin/kg body weight/min) and glucose tolerance were assessed. The glucose disposal rate was 23.0 +/- 10.1 mumol/kg/min (mean +/- S.D.), indicating moderate insulin resistance in these patients. We found no association between basal muscle glycogen content and basal or postprandial respiratory quotient, insulin sensitivity, nutritional status or glucose tolerance. However, there was a positive correlation between muscle glycogen content and exercise, as well as insulin-induced respiratory quotient (r = 0.651, p < 0.03 and r = 0.587, p < 0.03, respectively). We conclude that postabsorptive muscle glycogen stores, which are effectively maintained in patients with cirrhosis, are one determinant of exercise-induced and insulin-induced whole body fuel metabolism in these patients.