Small intestinal biopsy was performed in all 100 first-degree relatives of 32 index patients with childhood coeliac disease (CD) diagnosed according to the European Society for Paediatric Gastroenterology and Nutrition. CD was found in 2 relatives (2.0%), which means that first-degree relatives of coeliac children would run a ten-fold increased risk of CD compared with the general population of Sweden. Five relatives had a moderately abnormal mucosa. On rebiopsy they had a normal mucosa and are therefore not classified as having CD according to current diagnostic criteria. For practical purposes it would be impossible to perform a biopsy in all first-degree relatives of coeliac patients. However, relatives with a past history of symptoms suggestive of malabsorption and relatives with present signs of malabsorption should be candidates for biopsy.