BACKGROUND: Several studies have shown that celiac disease, an autoimmune disorder that occurs in genetically susceptible individuals, is highly prevalent among relatives of celiac patients. AIM: To determine the prevalence of celiac disease in a group of first degree relatives of Brazilian celiac patients. METHODS: First degree relatives of celiac patients attending the Brasilia University Hospital Pediatric Gastroenterology Outpatient Clinic or the Celiac Disease Investigation Center, Brasília, DF, Brazil, between March 2001 and November 2004 were invited to undergo serological screening for celiac disease applying the IgA anti-endomysium antibody test (IgA-EMA). All positive IgA-EMA sera underwent a second screening using the IgA anti-tissue transglutaminase antibodies test. Duodenal or small intestinal biopsies were performed in all subjects positive to serological testing. Biopsy samples were classified as type (O) normal, (I) infiltrative, (II) infiltrative hyperplastic, (III) flat destructive, and (IV) atrophic hypoplastic. The final diagnosis was ascertained in subjects showing positive serological tests and a grade I to III small intestinal lesion. RESULTS: Nine new cases of celiac disease were found among the 188 first degree relatives tested (4.8%). CONCLUSION: The present study confirms the high prevalence of celiac disease among first degree celiac patients relatives and reinforces the need of extensive diagnostic screening in this specific group.