Introduction: Various disease- specific serum antibodies were described in patients with inflammatory bowel disease and their yet healthy first- degree relatives. In the latter, serum antibodies are commonly regarded as potential markers of disease susceptibility. The present long- term follow- up study evaluated the fate of antibody- positive first- degree relatives. Patients and Methods: 25 patients with Crohn s disease, 19 patients with ulcerative colitis and 102 first- degree relatives in whom presence of ASCA, pANCA, pancreatic- and goblet- cell antibodies had been assessed were enrolled. The number of incident cases with inflammatory bowel disease was compared between antibody- positive and antibody- negative first- degree relatives 7 years after storage of serum samples. Results: 34 of 102 (33% ) first- degree relatives were positive for at least one of the studied serum antibodies. In the group of first- degree relatives, one case of Crohn s disease and one case of ulcerative colitis were diagnosed during the follow- up period. However, both relatives did not display any of the investigated serum antibodies (p = 1). Discussion: The findings of our pilot study argue against a role of serum antibodies as a marker of disease susceptibility in first- degree relatives of patients with inflammatory bowel disease. However, these data have to await confirmation in larger ideally prospective multicenter studies before definite conclusions can be drawn. Introduction: Various disease-specific serum antibodies were described in patients with inflammatory bowel disease and their yet healthy first-degree relatives. In the latter, serum antibodies are generally considered as potential markers of disease susceptibility. The present long- term follow-up study evaluated the fate of antibody- positive first-degree relatives. Patients and Methods: 25 patients with Crohn’s disease, 19 patients with ulcerative colitis and 102 first-degree relatives in whom presence of ASCA, pANCA, pancreatic- and goblet-cell antibodies had been assessed were enrolled. The number of incident cases with inflammatory bowel disease was compared between antibody- positive and antibody- negative first-degree relatives 7 years after storage of serum samples. Results: 34 of 102 (33%) first-degree relatives were positive for at least one of the studied serum antibodies. In the group of first-degree relatives, one case of Crohn’s disease and one case of ulcera However, both relatives did not display any of the investigated serum antibodies (p = 1). Discussion: The findings of our pilot study argue against a role of serum antibodies as a marker of disease Susceptibility in first-degree relatives of patients with inflammatory bowel disease. However, these data have to await confirmation in larger ideally prospective multicenter studies before indefinable conclusions can be drawn.