Infrared thermograms were made with a scanning radiometer of 15 nude subjects exposed to environments of 4° and 23° C for two hours and sweating subjects exposed to an environment of 27° C for 10 minutes. Surface temperatures of 41 different body areas were determined by relating calculated temperature values for a gray scale on each thermogram with densitometer readings. Surface temperatures were found to be more variable in the cold, 8° to 15° C, with an average mean temperature of 11° C. The nose, pectoral area, patella, gluteus maximus and fatty tissue about the waist were cold regions whereas the upper chest, forehead and spinal column were warm regions. In a comfortable environment, the subjects' surface temperatures were less variable, 25° to 29° C. Surface temperatures of subjects in comfort environments show similar differences between identical body regions as seen in the cold, but the magnitude of the temperature gradients was less. Sweating subjects had uniform surface temperatures, mean 33° C, with only small variations. These data were used to compare various methods for determining mean skin temperatures.