Maximal voluntary contraction (MVC) using a handgrip dynamometer was assessed in seventy-two young adult males. The subjects were divided into two groups on the basis of a BMI of 18·5 kg/m2. The subjects with a BMI < 18·5 kg/m2 (n 38) were further divided into an underweight (UW;n 20) group and a chronically energy-deficient (CED; n 18) group. The CED subjects had significantly lower MVC (30·1, SD 5·9 kg) than either the well-nourished controls (BMI > 18·5 kg/m2: 39·8, SD 5·8 kg) or the underweight group (37·6, SD 4·9 kg). The differences between the CED and UW groups persisted even after the MVC were corrected for forearm muscle area and stature. The results suggest that MVC may be a useful functional indicator of nutritional status particularly in differentiating subjects with chronic undernutrition from individuals who are underweight and not undernourished but have similar BMI.