Polyester (polyethylene terephthalate) is one of the most widely used polymers in textiles. Despite all the advantages of this polymer, its low thermal resistance limits its use in filters and protective textiles. On the other hand, polyester nonwovens are used in many products as wipes, filters, and padding. The surface properties of polyester nonwovens are often not perfect for a specific application and need to be modified. Different ways, including coating, have been developed to modify their surface properties. Therefore, in the present study attempts were made to investigate the improvement of the thermal resistance of a polyester nonwoven by coating. A polytetrafluoroethylene (PTFE) coating was applied to improve the thermal and flame resistance of this fabric. The mechanical properties of coated samples were examined as well. According to the results, surface coating using PTFE is effective in terms of flame retardancy and controlling the thermal shrink of polyester nonwovens. The mechanical properties of the coated samples were also improved.