We present the application of nanogels with high functional β-cyclodextrin (β-CD) content as new and versatile method for the modification and protection of textiles. The complexation potential of covalently embedded β-CD in nanogels is demonstrated for the common insecticide permethrin in aqueous environment. It is shown that permethrin containing β-CD nanogels can be applied easily, homogeneously and safely on keratin fibers like wool fabrics and human hairs. The permethrin concentration on fibers is directly controlled by the permethrin content in nanogels. We tested the permanence of permethrin on treated fibers with regard to washing and UV fastness. Our results show that permethrin complexed in nanogels is removed from the textile during washing, but that the complexation of permethrin by β-CD domains in the nanogels protects the active ingredient from UV degradation. Bioassay tests against the larvae of Tineola bisselliella and Anthrenocerus australis show that the activity of the ingredients does not decrease after complexation in β-CD gels and it results in protection of the wool fibers against degradation by the insect larvae.