This study examined the relationship between the menstrual cycle, the stress process, andmigraines. Women migraineurs (N=12) and a matched control sample (N=12) completed a set ofquestionnaires assessing stress, appraisal, and coping at premenses, menses, and ovulation. Inaddition, migraineurs completed a month of daily headache recording. Analyses revealed that themenstrual cycle affected subjects' use of coping strategies and migraineurs' headache activity.Analyses also showed that the covariation between stress and migraine varied across the menstrualcycle. These results support the hypothesis of a three-way relationship between menstrual cycle,stress, and migraine. We suggest that physiological and/or psychological changes associated withpremenses may enhance or strengthen the relationship between stress and migraine.