This work was focused on the development of flame retardant cotton fabric by coating with intumescent formulations containing different polymers and inorganic additives. The thermal degradation study was carried out using thermogravimetric and differential scanning calorimeter techniques, and the flame retardancy behaviour was evaluated by auto flammability and limiting oxygen index tests. Coated cotton fabric samples give rise to high char yields on heating with lower degradation temperature at the expense of volatile products. The action of intumescent coating materials was found concurrent with the process of decomposition of cotton fabric on heating. The FTIR spectra of chars of coated cotton fabric indicated the catalyzed dehydration of cotton cellulose and contribution of phosphorus for formation of carbonaceous char. The coated cotton fabric samples have achieved better flame retardant properties and were not ignited during auto flammability test.