Composite solid rocket propellants based on hydroxy terminated polybutadiene (HTPB) have become the workhorse propellants in solid rocket motors world-wide. It was reported that polymers containing azide groups exhibit an interesting feature. On pyrolysis or combustion they liberate extra heat due to the scission of the azide bond which is highly exothermic. In this paper energetic polymeric binder based on azido hydroxy terminated polybutadiene (AHTPB) was proposed, prepared and characterized. The synthesis was started by brominating the commercial hydroxy terminated polybutadiene (HTPB), followed by its refluxing with sodium azide for about 30 hours. The investigated propellant formulations were based on mixtures of the prepared energetic binder (AHTPB) (13%) with different nitrogen content, ammonium perchlorate (71%) and Aluminum (16%).The performance of these propellant formulations was deduced through a computer program. Also, the effect of nitrogen content variation of the polymeric fuel binder on the specific impulse and the adiabatic flame temperature was investigated.