In 14 persons the skin temperature has been measured by means of thermistor thermometer. The influence of the shape of the probe and the pressure exerted on the resulting value of the skin temperature has been proved. In 10 additional men the relation of the temperature difference (deltaT) to the exerted pressure (P) was determined, the regression equations were derived for relation deltaT/P, and the correlation coefficients for recalculation of the temperatures measured by thermistor thermometer with the pressure exerted 20 g to values determined by thermovision. The skin temperature values determined by thermography were used in 24 formulas (3–16 points) for calculation of mean skin temperature. The differences of the means in determining the optimal method (16 points) were evaluated by the t-test and by the percentage expression of aggrement for criteria plus or minus 0.1, plus or minus 0.2, plus or minus 0.5, and plus or minus 0.1 degrees C. For precise laboratory work 10 points of measurement are recommended; for measurement in the field 6 points of measurement are enough. Orientational measurement can be performed very well by means of Ramanathan method (4 points).