A large amount of the textile waste produced during the manufacturing of clothing and other textile products is polyester/cellulosic fabrics such as polyester/cotton and polyester/rayon blends. The possibility of using thermal methods such as thermogravimetric/differential thermal analysis (TG/DTA) and differential scanning calorimetry (DSC) to determine the efficiency of methods for separating cotton and polyester from fabrics made of intimately blended fibers was investigated. Both were confirmed as efficient methods for rapid estimation of the polyester content of blended fabrics.