Eysenck's personality inventory (EPI) was administered to 653 females and 666 males. Item analyses were carried out for the subsamples and the combined sample. In addition hierarchical oblique factor analysis was applied to the data. The purpose of both item and factor analysis was to examine the psychometric properties of the EPI in regard to (a) the homogeneity of the scales, in terms both of internal and external item-scale relationships (b) the univocality of the scales assessed in factor analytic terms. It was found that the neuroticism scale was superior to the extraversion scale in both these respects.