Stair-like metamagnetic transitions in the oxygen deficient La0.5Ca0.5MnO3-delta perovskite are here for first time reported. This experimental fact sheds light on the knowledge of metamagnetic transition in anion deficient phase segregations systems. Actually, it is shown that controlled reduction of the oxygen content constitutes an alternative pathway to the chemical doping at the A and B positions of the perovskite sublattice. In this way, point defects are created inducing the stair-like transition in a CE-type AFM (antiferromagnetic) manganite.