Superoxide dismutase and glutathione peroxidase activities were determined in isolated neurons and glial cells as derived from adult male rat brain. Glial enzyme activities were higher than in neurones, and the glial enzymes may be an important source of the enzyme activities in the homogenate, postmicrosomal fractions and in the whole brain microsomes. For comparison, glial cells showed also higher diaphorase activity than neurons which may stress the importance of glial cells in the oxidative metabolism of exogenous chemicals in brain.