The value of mean skin temperature as an estimate of energy expenditure was verified in a sample of 10 normal-weight adult male subjects. Measurements were carried out with thermometric probes under conditions of rest and environmental thermoneutrality. Total heat losses were then calculated through a computerized complex mathematical formula. The value for mean energy expenditure obtained in this manner (100.2 +/- 7.02 kcal/h) is extremely close to the value for theoretical metabolism derived from the predictive equations in the literature (95.01 +/- 6.14). This verification of the validity of transforming cutaneous temperature data into energy expenditure, in accurately standardized experimental conditions, confirms the importance that the value of mean skin temperature, in the area of variability among individuals, can have in conditioning the energy balance at different levels, for a given caloric intake and with all other parameters being equal (age, sex, physical activity). In this connection, these results suggest that skin temperature may play a role in the pathogenesis of obesity.