The objective of the present study was to compare the ability of acute physiology and chronic health evaluation (APACHE) scoring systems with the combination of an anthropometric variable score "adductor pollicis muscle (APM) thickness" to the APACHE systems in predicting mortality in the ICU. Three hundred and four patients enrolled in this prospective observational study. The APM thickness in dominant hand and APACHE II and III scores were measured for each patient upon admission. Given scores for the APM thickness, were added to APACHE score systems to make two composite scores of APACHE II- APM and APACHE III- APM. The accuracy of the two composite models and APACHE II and III systems in predicting mortality of patients was compared using area under the ROC curve.