No nutrition assessment tools specifically tailored for intensive care unit (ICU) patients have been developed and validated in Singapore. Studies conducted in Brazilian populations suggest that the thickness of the adductor pollicis muscle (TAPM) may be used to assess nutritional status and predict mortality of critically ill patients. The aim of this study was to determine if TAPM can be used as a predictive indicator of mortality in Singapore ICU patients. TAPM values were obtained using skinfold calipers in 229 patients admitted to the medical ICU. TAPM measured in both hands showed no significant correlation with either the primary outcome (28-day mortality) or secondary outcomes (hospital outcome and hospital length of stay). This study demonstrated that TAPM does not predict 28-day mortality and hospital outcome, and is not correlated to length of stay in Singapore ICU patients. More studies are necessary to validate the use of TAPM as an anthropometric indicator of ICU outcome in other regions of the world.