Ink composition for inkjet textile printing and textile printing method for fibers with use of same

Provided are: an ink composition for inkjet textile printing, which contains at least two kinds of yellow reactive dyes; and fibers which are dyed with this ink composition for inkjet textile printing. Also provided is a textile printing method for fibers, which comprises: an adhesion step wherein this ink composition for inkjet textile printing is used as an ink and droplets of the ink are ejected by an inkjet printer so as to adhere to fibers; a reactive fixing step wherein a dye in the ink, which has been caused to adhere to the fibers in the adhesion step, is reacted to be fixed to the fibers by means of heat; and a cleaning step wherein the dye remaining unfixed in the fibers is removed.