The dyeing properties of the several reactive dyes possessing different types of the reactive group on nylon 6 fabric have been investigated. Dyeing of nylon fiber with commercial reactive dyes was dependent on the dye bath pH. As pH increased, the extent of exhaustion decreased due to the deprotonation of the amino end group. But, the extent of fixation increased because of the enhanced reactivity with nylon fiber. It was found that all reactive dyes could be applied to nylon 6 reasonably at pH 5-6. But, the conflicting requirements of dye exhaustion and covalent bond formation limited the extent of fixation efficiency. The best method to improve the extent of the fixation efficiency of the reactive dyes was the conversion of sulphatoethylsulphone group to vinylsulphone group before dyeing with trisodium phosphate. The converted Supra type reactive dye gave the highest extent of fixation efficiency, which was about 90%.