The parameters of solar radiation affecting man in Antarctica are considered, using data from two coastal stations and from the South Pole. Observations of solar radiation and its effects on clothing and skin temperatures of men standing on snow at Scott Base are reported. From measurements of the spectral reflectance of the outer garments and the regional thermal insulation of the clothing made subsequently, the solar heat gain at the clothing surface and its effect on heat transmission through the clothing and on heat loss to the environment were calculated. The effective surface area of the clothed body surface exposed to direct and reflected solar radiation, and the effective surface areas concerned in low temperature radiation exchange and convective heat loss, are considered. An attempt was made to determine these areas by direct measurement. The results were used to calculate values for the solar heat gain by the whole body and the cooling power of the environment under Antarctic conditions, the combined effects of which are expressed in terms of a temperature increment to be added to the ambient air temperature.