Migraine and asthma have been reported to occur in the same person more commonly than would be expected if they are independent. The large Collaborative Perinatal Project provided an opportunity to see if children born to women with migraine or with the group of disorders characterized by asthma and/or allergies were more likely to manifest asthma or eczema in the first 7 years of life. Among children whose mothers had neither migraine nor asthma/allergies, 3.2% had asthma. Of children whose mothers had migraine, but not asthma/allergies, more than 6% had asthma. The risk of asthma among children born to women who had both migraine and asthma/allergies was greater than the risk associated with each maternal disease. The risk of eczema in children was not appreciably influenced by the mother's propensity to migraine or asthma/allergies. The results of this first study of migraine in one generation and asthma in the next lead to the conclusion that the two disorders are probably related.