Pure calcium sulfate (CS) is an excellent bone graft material because it is biocompatible, completely biodegradable, osteoconductive, safe, nontoxic and angiogenic. It also has barrier properties. However, its rapid degradation limits its use as a bone graft material. A nanocomposite of CS and poly (l lactic acid) (PLLA) in a ratio of 96:4 was developed to overcome this problem. This composite underwent slower degradation. It took 16 weeks for complete degradation whereas pure CS takes only 4 weeks. When implanted in bone defects in rabbits, it underwent complete degradation and stimulated vigorous bone formation.