The thermal insulation of clothing is one of the most important parameters used in the thermal comfort model adopted by the International Standards Organization (ISO 1995) and by ASHRAE (2005). To date, thermal insulation values for various types of clothing ensembles from different geographical regions, i.e., Western, Chinese, Korean, etc., have been investigated and suitable values adopted in these standards. However, many other types of clothing, such as those worn in the Arabian Gulf region, have not been investigated to date. Thus, the main objective of the present study is to measure the thermal insulation values (clo) of a number of garments for males in the Arabian Gulf. The clothing ensembles and garments of Arabian Gulf males presented in this study are representative of those typically worn in the region during both summer and winter seasons. Measurements of total thermal insulation values (clo) were obtained using a thermal manikin in accordance with the definition of insulation as given in ISO 9920 (ISO 2006). The clothing area factor (fcl) for Arabian Gulf men's garments and ensembles was determined in this study using a photographic technique and by regression based on the insulation values. In addition, fiber content, descriptions, and weights of Arabian Gulf clothing were recorded and tabulated in this study. The findings of this study are presented as additions to the existing knowledge base regarding clothing insulation and provide, for the first time, data for Arabian Gulf clothing. [ABSTRACT FROM AUTHOR]