The surface of an ethylene-vinyl alcohol copolymer (EVOH) was modified with Ti-OH groups by a silane coupling treatment followed by treatment with a titania solution. The arrangement of the Ti-OH groups formed on EVOH was changed from amorphous into anatase structure by a subsequent HCl solution treatment. Bonelike nanoapatite was successfully formed on the surface-modified EVOH even in a form of fibers as well as plates within 2d at 36.5°C in a simulated body fluid (SBF) with ion concentrations approximately equal to those of human blood plasma. The resultant nanoapatite-polymer fiber composite was similar to that of natural bone in its structure where apatite nanocrystals are deposited on fine organic fibers constituting a composite. Therefore, if the present surface modification can be applied to a three-dimensional fabric with a structure similar to the collagen fibers of natural bone, a composite with an analogous structure to that of natural bone would be obtained. The resultant composite is expected to exhibit mechanical properties analogous to those of natural bone, as well as bone-bonding ability, and hence be truly useful as a new bone substitute.