Abstract: Wool keratin has natural flame resistant properties such as higher ignition temperature and limiting oxygen index than other natural fibers. In this study, keratin extracted from human hair was used as a flame retardant onto cotton fabric. Moreover, the keratin was also combined with Ammonium Polyphosphate (AP423) to study the synergistic flame retardant action onto cotton fabric. The extracted human hair keratin and finished cotton fabric were then characterized by FTIR and TGA. The flame retardancy was investigated using UL94 tester according to ASTM D 4804 thin material vertical burning test. Cotton fabric treated with 10% AP423 alone exhibited excellent flame retardancy (VTM 0) whereas with 5% extracted keratin alone did not. However, the addition of only 5% AP 423 and 5% extracted keratin improved flame retardancy from no rating to VTM 1.