Argon plasma-induced graft polymerization of (ethylene glycol) methacrylate phosphate (EGMAP) was performed on the polyamide-6 (PA6) surface to improve the fire retardancy properties. The surface composition and morphologies of the PA6-g-poly(EGMAP) surfaces were then characterized by Attenuated total reflection-Infrared and Scanning electron microscopy. The thermal properties were investigated by using Thermogravimetry analysis. It was found that weight loss rate of the grafted substrates was lower, as compared to the virgin PA6. The results obtained showed also that the grafting allows to obtaining a residue of about 30% at 600 degrees C, temperature at which the virgin PA-6 was totally decomposed.