Hydrogel series composed of starch/N-vinylpyrrolidone (starch/NVP) have been synthesized by means of -radiation-induced graft copolymerization and crosslinking process. Optimization of the preparation conditions was achieved to ensure the highest gelation degree. The produced hydrogels were characterized using fourier transform spectroscopy, as well as by studying their swelling behavior. In situdeposition of hydroxyapatite (HAp) was achieved via alternate soaking technique. The developed nanocomposites nHAp-(starch/NVP) were characterized using energy dispersive X-ray spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy. Mechanical study revealed that the compressive strength of the composites increased initially after thefirst cycle of deposition, then it decreased gradually by increasing the number of the deposition cycles. In vitro bioactivity and blood compatibility evaluation of the obtained nanocomposites indicated that these nanocomposites were both bioactive and biocompatible. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013