The comparative diagnostic value of IgA anti-endomysium and IgA antigliadin antibodies in adults with histologically confirmed celiac disease is reported. Sera from 144 adult patients (without concurrent dermatitis herpetiformis or IgA deficiency) who underwent small bowel biopsy were analyzed for both IgA anti-endomysium and IgA anti-gliadin antibodies. Nineteen patients (13%) had celiac disease. The presence of IgA antiendomysium antibodies had a sensitivity of 74% and a specificity of 100%. The positive and negative predictive values were 100% and 96%, respectively, and the diagnostic accuracy was 97%. In contrast, IgA anti-gliadin antibodies had positive and negative predictive values of 28% and 96%, respectively, with a diagnostic accuracy of 71%. Based on these data, we suggest that small bowel biopsy is not necessary to diagnose celiac disease in symptomatic adults with IgA antiendomysium antibodies. Due to a negative predictive value of 96%, some symptomatic adults lacking anti-endomysium antibodies will not be correctly diagnosed without small bowel biopsy.