A private practice was surveyed for prevalence of inflammatory bowel disease (IBD) in husband-wife partners and in their children. Among approximately 2500 patients with IBD in our files, 19 couples were identified. They were subdivided into group A (n = 5) in which both partners had symptoms of IBD before marriage; group B (n = 7) in which only one spouse had IBD before marriage and the other partner experienced symptoms afterwards; and group C (n = 7) in which neither spouse had symptoms before marriage but IBD subsequently developed in both. In group B, the disease developed in the second spouse 2-16 years after marriage (mean, 6.4 years). In group C, IBD developed in the first spouse 0.3-41 years after marriage and in the second spouse 1-14 years after the first spouse (mean, 6.8 years). Thirty-five children have been born to 16 of the couples. Two children died before age 20. Of the surviving 33 children, IBD has already developed in 12 (36%). Among the other 21 unaffected children, 1 had uveitis at age 9 and 10 are still under the age of 21, perhaps too young to have yet developed IBD. The frequency of IBD in children was slightly higher if both parents had already developed IBD at the time of conception (67%) compared with when only 1 parent (50%) or neither parent (50%) had developed IBD when conception occurred. Although these data do not distinguish genetic from environmental factors, they show a higher risk of IBD in children when both parents have this illness.