OBJECTIVE Liver biopsy examination is the gold standard to diagnose the presence of cirrhosis. The aim of this study was to evaluate the accuracy of both 13 C-aminopyrine breath test ( 13 C-ABT) and 13 C-galactose breath test ( 13 C-GBT) in the noninvasive assessment of the presence of cirrhosis in patients with chronic liver disease. METHODS We evaluated 61 patients with chronic liver disease of diverse etiologies (21 compensated cirrhosis). All patients underwent 13 C-GBT and 13 C-ABT, and the results were expressed as a percentage of the administered dose of 13 C recovered per hour (%dose/h) and as the cumulative percentage of administered dose of 13 C recovered over time (%dose cumulative). Results were analyzed according to absence vs presence of cirrhosis. RESULTS On average, 13 C-GBT %dose/h and %dose cumulative were decreased significantly in patients with compensated cirrhosis, and the same finding was observed for 13 C-ABT results from 30 to 120 minutes. 13 C-GBT %dose/h at 120 minutes had 71.4% sensitivity, 85.0% specificity, and 83.7% accuracy, whereas 13 C-ABT %dose cumulative at 30 minutes had 85.7% sensitivity, 67.5% specificity, and 77.1% accuracy for distinguishing between the 2 subgroups of patients. Combined assessment of 13 C-GBT and 13 C-ABT increased the diagnostic accuracy (80% positive predictive value) of either test alone and reached 92.5% specificity and 100% sensitivity for the diagnosis of cirrhosis. CONCLUSIONS In patients with chronic liver disease, both 13 C-GBT and 13 C-ABT are useful for the diagnosis of cirrhosis. Combination of the tests increases the diagnostic yield of each test alone.