Familial aspects of inflammatory bowel disease (IBD) were assessed as part of an age and sex matched case control study of 91 children with IBD and 131 controls The prevalence of IBD in family members of the children was studied, the affected side (mother's side or father's side) of the family was documented and the type of inflammatory bowel disease was traced among relatives Data were collected from children in out-patient clinics at a large urban tertiary-care facility All family data were verified with the affected relatives and/or their physicians The children with IBD (the cases) had significantly (P=0 0000385) more IBD in their families than the controls Among all children with IBD in their family, IBD was found significantly (P=0 0073) more often on the mother's side of the family than on the father's side Patterns of disease varied within families A mixture of ulcerative colitis and Crohn's disease was found within families The implications of the findings are discussed Directions for prevention, screening, early intervention and further study are given