Laboratory experiments were performed to investigate the photochemical reactions of H2O2 and HCHO in artificial snow under natural conditions. Artificially-made snow doped with different concentrations of H2O2 or HCHO was irradiated in the UV and visible range resulting in the decomposition of both compounds. It was found that the decompositions followed first-order decay rates suggesting photolysis reactions. Experiments were performed with a wide range of initial concentrations. The results indicated that the photolysis rate of H2O2 was not affected by the initial concentration, which was contrary to the case of HCHO where preliminary experiments demonstrate that the photolysis rate depends on the initial concentration. H2O2 was observed to decompose faster than HCHO under similar conditions. Such reactions, if the products are similar to the products of the photolysis of H2O2 and HCHO in the gas phase, can serve as sources of highly reactive radicals such as OH and HO2 in surface snow, which could affect the concentrations of other trace compounds in natural snow covers. Furthermore, the reactions could have an impact on profiles of H2O2 and HCHO in surface snow and the exchange of these species between snow-covered regions and the atmospheric boundary layer.