Abstract: Crimped bicomponent-filament yarn is produced by spinning composite filaments of polyhexamethyleneadipamide and polyethylene terephthalate modified with 5-(sodium sulfo) isophthalate, with the two components side by side in oblong filament cross sections wherein the length of the major axis is 2.5 to 4.5 times the length of the minor axis and the polyhexamethyleneadipamide component occupies 20 to 35 percent of the total cross-sectional area, drawing the filaments about 3 .times. in about 200.degree. C steam, and crimping the filaments in a bulking jet with air or steam at about 280.degree. C. The composite filaments have a randomly reversing filament twist with an average of 60 to 120 crimps per inch (23.5 to 47 crimps/cm) of filament and, when the yarn is heated at about 100.degree. C in aqueous caustic solution, filament components split apart to form a yarn having crimped copolyester filaments surrounded by arched filaments of polyhexamethyleneadipamide.