Hydrofullerides with hydrogen content up to 5 Wt.&percent; were obtained by direct and catalytic reaction with H2gas. Hydrogen content was monitoredin situusing gravimetric system and verified by chemical analysisex situ. It was found that pure C60reacts rapidly when exposed to H2gas at 673 K and 50–100 Bar. Gravimetric study of this reaction showed that hydrogenation is saturated at about 5 at.&percent; of hydrogen. Mass of the sample goes through a maximum and with a longer reaction time its weight start to decrease. This proves that hydrofullerides with high hydrogen content are not stable and strong hydrogenation results in collapse of C60molecules. XRD study showed that samples prepared by direct hydrogenation without catalyst retain an original FCC structure with increase of cell parameter up toa=15.1Å. Catalytic hydrogenation of C60with H2gas results in decrease of the reaction temperature and formation of hydrofullerides with new crystal structure (suggestively sc). © 2003 American Institute of Physics