The Egyptian extra long stapled cotton "GIZA76" which has a very good mechanical and chemical properties [I] was selected as a raw material to obtain nitrocellulose energetic fibres, such fibres can be used as a reinforcing agent in propellant formulations instead of inert fibres to improve not oniy the mechanical properties of composite propellants but also, the burning rate of such propellant . The effect of either chopped or nonchopped nitrocellulose fibres length and content on the mechanical properties of the prepared propellant samples were examined .Also, the effect of bonding agent on the reinforcing fibres has been investigated .Satisfactory results have been obtained.