• Cnsiderable research supports the widespread complaint of mood and behavioral changes during the menstrual cycle. However, there is little evidence of effects on intellectual performance, even though students commonly complain of it. We studied the results obtained by 244 female medical and paramedical students in all examinations taken during one year. In view of suspected correlations between personality characteristics and degree of dysmenorrhea, an Eysenck Personality Inventory, measuring extroversion and neuroticism, was administered. The examination results of high and low scorers on these personality scales and of those women with prolonged (≥ six days) menses were reanalyzed. Not one of these analyses revealed significant menstrual-cycle effects on examination performance. Thus, while some persons may suffer, it does not seem that menstrual cycle effects are sufficient to handicap significantly the examination performance of the majority of female students.