To produce high performance antithrombus elastomers, a series of new fluorine-containing segmented poly(urethane-urea)s was synthesized from 2,2,3,3,4,4,5,5-octafluorohexamethylene diisocyanate (1) and α-hydro-ω-hydroxypoly(oxyalkylene)s (5a, b and 6) or fluorinated dioxa-1,10-decanediols (3 and 4) (as the soft segments) via the prepolymers (7) which subsequently were reacted with various diamines including a fluorinated aliphatic diamine (2) as chain-extenders. High-molecular-weight polymers were obtained in high yields with 5a and nonfluorinated diamines. Spectroscopic analysis of the prepolymers and the chain-extended polymers indicated their structures to be highly ordered. Stress-strain curves of films cast from a DMF solution indicated the polymers to be typical elastomers with tensile strength as much as 600–700 kg/cm2.