The interaction of hydrogen peroxide aqueous solutions with crude oil and high-boiling refined products, such as fuel oil and vacuum gas oil, in the presence of an oxidative cracking catalyst in the form of iron oxide nanosized particles is studied. This study is aimed at modeling processes occurring in the case of using hydrogen peroxide solutions in the catalytic cracking of crude oil. It is found that, in the presence of iron particles, the reaction of hydrogen peroxide decomposition causes the cracking of petroleum hydrocarbons. This process may be accompanied by reduction in the viscosity and density of crude oil and refined products. The reaction of catalytic cracking performed under these conditions leads to a marked increase in the fraction of light hydrocarbons in the composition of crude oil and high-boiling refined products.