N anoscalec omposites of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and polymeric bindersw ere produced by co-precipitation using rapid expansion of supercritical solutions( RESS). The binders used in this study are poly (vinylidene fluoride-co-hexafluoropropylene) (VDF-HFP 22 )a nd polystyrene (PS). The RDX/VDF-HFP 22 and RDX/PS co-precipitatedn anoparticles were characterized by Scanning Electron Microscopy( SEM) and Transmission Electron Microscopy( TEM). The average size of produced nanoparticles is ca. 100 nm. TEM analysis of RDX/PS nanocomposite shows ac ore-shell structure with RDX as the core material and the shell consistingo ft he polymeric binder.X -ray Powder Diffraction( XRPD) analysis indicates polycrystalline structure of RDX in the product with ac rystallite size of 42 nm. The content of RDX in the composite particles is in the range of 70-73 %b ym ass as determinedb yG as Chromatography Mass Spectroscopy( GCMS)and by XRPD.