Insect repellency of fiber is a property which makes the fiber to be of interest in the field of military and health. The insect-repellent substrate could be prepared using either functional finishing or applying an insect-repellent dye. In this article, insect-repellent nylon 6 is obtained using a novel insect-repellent reactive dye containing N,N-diethyl-m-toluamide. To do this, N,N-diethyl-m-toluamide (DEET) was first nitrated at the p-position relative to amide functionality. The nitrated product was reduced in the presence of C2H5OH, SnCl2, and HCl. The produced amine was then condensed with 2,4,6-trichloro-1,3,5-triazine (cyanuric chloride) as a reactive group in below 5 degrees C. The resultant adduct was finally reacted with an amino group present in 6-amino-1-hydroxy naphthalene-3-sulfonic acid (J-acid) to produce 7-(4-chloro-6-(4-(diethylcarbamoyl)-2-methylphenylamino)-1,3,5-triazin-2-ylamino)-4-hydroxynaphthalene-2-sulfonic acid. To synthesis azo dye, sulfanilic acid was diazotized using HCl and NaNO2 and then coupled to the above prepared component to produce insect-repellent reactive dye. An analog dye was prepared via the same route without insect-repellent group making stage. The chemical structures of the novel dyes were characterized using FTIR and 1H-NMR spectroscopy. The spectroscopic properties of the dyes were determined in terms of ?max and emax in aqueous solution. The novel dyes were then reacted with nylon 6 and bonded to it covalently to provide permanent insect-repellent substrate. The insect-repellent efficacy of the reacted nylon 6 was studied using standard methods for Anophele mosquito repellent. The insect-repellent dye reacted nylon 6 showed insect-repellent activity. (c) 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012