A review focused on homogeneous and heterogeneous catalytic oxidations in dense CO2 is presented. The review also included examples of the use of diluted peroxides like as aqueous H2O2 and t-BuOOH and some work that used molecular oxygen as oxidant. A discussion on the potential and limitation of the dense CO2 as media for catalytic oxidations was also included in the review. Abdulagatove and co-workers complied experimental data on the critical properties of binary mixtures composed of CO2 and O2. Iwata and co-workers demonstrated the O-exchange reactions between CO2 and O2 over copper- and manganese-mixed oxide. These exchange reactions involved the oxygen exchange between metal oxides and gases. It was concluded that wrong amount of dense CO2 medium in catalytic oxidations could reduce the process efficiency and sustainability.