After appropriate transformations age regression parameters for relative band power values were determined in two groups of normal subjects (94 men and 80 women) between 20 and 70 years of age. Four homologous bipolar derivations over each hemisphere were considered. For most regression equations significant sex differences were found for the intercept values; a sex difference for the regression coefficient was only present for the temporal theta power. The use of patient and control groups composed solely of subjects of the same sex can be indicated when studying groups of subjects with minor qEEG disturbances, an example of which is given.