Pretreatment of Quiana polyamide fabric (Q-PA) with some ketones was performed to induce some structural changes in order to improve fibre dyeability. Isothermal shrinkage rate curves of modified Q-PA were characterized by an induction period. The molecular volume of the interacting ketones/solvents influenced the corresponding energy of diffusion (ΔE) into the polymer. The difference in ΔE among the ketones/solvent may be associated with some difference in their binding capacity with the substrate. The dynamic shrinkage increased sharply with increasing temperature of pretreatment. Measurement of iodine sorption by modified polyamide allowed detection of induced structural differences.Changes in capability of modified polyamide to uptake cationic dyes were noticed. Evaluation of time of half dyeing and specific dyeing rate constant indicated that the pretreatment had more powerful influence in disordering polyamide fibre structure. The rate of dye diffusion in the modified polymer increased with rise of dyeing temperature. The apparent activation energy of diffusion showed the ability of the dye molecules to move within the fibre matrix. Calculation of the dye affinity and heat of dyeing anticipated that more disorder in fine structure due to pretreatment was imparted.