In this study, a facile and green synthetic protocol for the synthesis of Gum Acacia assisted hydroxyapatite (GA-HAp) nanostructures and in-situ reduced gold nanoparticles in GA-HAp (GA-HAp-Au) by controlling size and shape using gum acacia (GA) is reported. GA acts both as crystal growth modifier for HAp particles and as a reducing agent for the synthesis of gold nanoparticles (3-13 nm). The HAp nanoparticles were prepared from cheap chemicals, orthophosphoric acid and calcium chloride at mild reaction conditions by chemical precipitation method. This protocol is monitored and studied to understand the various morphologies of HAp nanostructures at different reaction conditions. The interaction of carboxylate group of glucuronic acid present in GA With HAp particles regulates the nucleation and crystal growth of the formed nanoparticles. As-synthesized products were well characterized by various techniques and the catalytic activity of GA-HAp-Au is explored for the hydrogenation of nitrobenzene to aniline formation under gas phase reaction. (C) 2014 Elsevier B.V. All rights reserved.