This study was carried out to investigate the changes of thermal properties such as warmth retaining and contact warm/cool feeling of commercial dress shirts by repeated washing and drying by sun and dryer. Three kinds of fabrics such as cotton 100%, cotton/polyester 80/20% and polyester 100% were repeatedly washed and dried, and then used as specimen. Thermo Labo II type was employed to measure the thermal properties. At the same time, structural properties such as thickness, weight, bulk density, porosity, moisture vapor permeability and air permeability were analysed.