Cadmium (Cd) is neurotoxic metal which induces histopathological damage and oxidative stress through free radicals over production. Metallothionein (MT) is a protein able to scavenge free radicals and to chelate metals. In this study we describe the lipid peroxidation (LPO) and MT content in the brain of developing rats exposed at Cd 1 mg/kg/day intra peritoneally (i.p.) and dexamethasone (Dx) 2 mg/kg/day (i.p.) alone and combined during 5 days. At those doses, cadmium significantly increases the levels of LPO in parietal cortex, striatum and cerebellum as compared to a control group while, in the hippocampus no modifications in the LPO levels were observed. In the group treated with Cd+Dx, Dx significantly diminished the levels of LPO in parietal cortex, striatum and cerebellum. On the other hand, the MT levels showed a significant increase in all regions of the groups treated with Dx and Cd+Dx as compared with the control group. These results show that Dx treatment prevented the increase in LPO levels associated to Cd exposure, probably through the increase in MT content.