ABO(3) type perovskite systems, CaFe1-xCoxO3 (0 less than or equal to x less than or equal to 0.5) and Sr2/3La1/3Fe1-xCoxO3 (0 less than or equal to x less than or equal to 1) were prepared by using a high pressure technique in the presence of an oxidizer KClO4. The parent Fe4+-oxides, CaFeO3 and Sr2/3La1/3FeO3, are both characterized by a charge disproportionation leading to an antiferromagnetic and insulating state, which is 2Fe(4+) --> Fe3+ + Fe5+ for the former and 3Fe(11/3+) --> 2Fe(3+) + Fe5+ for the latter. The Co-substitution leads to a switching to a ferromagnetic and metallic phase. In comparison with the cubic Sr-analogue, the ferromagnetic Curie temperature is lower and the saturation magnetization is smaller, while the coercive force is larger and the resistivity is higher.