A process for fire-proofing treatment of shaped articles of aromatic polyamides which comprises contacting a shaped article of an aromatic polyamide with an aqueous solution of a phosphorus-containing inorganic compound free from halogen and sulfur, drying it and then post heat-treating it; characterized in that said shaped article is contacted with an aqueous solution of a treating compound selected from the group consisting of halogen- and sulfur-free, phosphorus-containing inorganic acids and their ammonium, amine and urea salts in a concentration of about 2 to about 30% by weight, dried at a temperature of not more than about 150.degree. C., and then post heat-treated at a temperature of about 300.degree. C. to about 450.degree. C.