High consumption of water and extensive use of volatile and toxic chemicals and solvents in textile industry lead to serious damage to the environment.Therefore, finding a suitable alternative for reducing water consumption, and, also the use of non-toxic solvents that have the suitable properties of conventional solvents, is an important need in the textile industry.Recently, ionic liquids(IL) have been introduced as so-called non-toxic and environmental friendly solvents and catalysts. It was demonstrated that ionic liquids are important in some textile processes, which reduce environmental pollution or improve the performance of manufactured textiles. IL may be used in the fiber production, weaving, dyeing, finishing and the wastewater treatment of textile dyeing processes.In more recent years, new ILs called protic ILs have been presented. These ILs have inexpensive reagents and simpler synthetic routes.In the present research an imidazolium based IL with the chloride anion and 2 diethanol amine based protic IL with chloride and acetate anion have been used. Two dyeing approaches using these ILs were chosen: ILs as dying assistants and ILs as dyeing medium. Then for each of the two approaches thermosol and high temperature (HT) dyeing methods were used. Experiments for the investigation into the effect of dyeing tempreture, dye concentration and L: R were conducted and the optimum conditions for the dyeing with IL were found.Kinetics and color fastness of dyeing with protic ionic liquids was investigated and it was showed promising results for dyeing with protic ILs as dyeing medium, which was comparable to the conventional HT dyeing.The surface properties of polyester fabric treated with protic ILs were investigated using SEM and FTIR; and the absorption of methylene blue dye. XRD and DSC tests of the treated and untreated polyester fabrics showed minor changes in crystallinity, however, the Tg of the fibers decreased significantly with increasing the temperature of the treatments.Finally wetting tests indicate increases in the wetting of polyester fabric due to the Dyeing with protic IL without affecting on the tensile strength of the fabric.