Since epoxides have found use as reagents, intermediate, end products, epoxidation of olefins and other organic substrates by inorganic oxidants catalysed by trasitional derivative has remained a primary goal in recent years. H 2 O 2 becomes an efficient epoxidising agent of unsaturated compounds under the catalytic action of certain transition metal derivative. We have examined the catalytic activity of W (VI) and Mo (VI) compounds in some oxidation reaction with H 2 O 2