Objective: to study the frequency of positive serology for celiac disease (CD) in patients with duodenal biopsies suggestive of this disease. Material and methods: cross sectional study. We included patients with duodenal biopsies histologically compatible with CD and antigliadin, antiendomysial and IgA antitransglutaminase antibodies. We defined a "case" of CD if there was a positive biopsy and either antiendomisial or antitransglutaminase positive antibodies. Results: thirty one patients were included in our study. Six were antiendomysial positive and 5 antitransglutaminase positive while the antigliadin was positive in 14 cases. Therefore, out of 31 patients only 10 had a serology compatible with CD and only one had positive both antibodies, antiendomysial and antitransglutaminase. Conclusions: a) we have found that most of the duodenal biopsies compatible with CD are not diagnosed with positive serology; and b) we found a low correlation between serological diagnostic tests. © 2010 ARÁN EDICIONES, S. L.