Objective: Several studies report a possible association of celiac disease (CD) with psychiatric and psychological disturbances, such as ADHD. Method: The authors assess 132 participants from 3 to 57 years of age (M = 19.3 years) affected by CD for the possibility of an associated ADHD-like symptomatology, using the Conner Scale Hypescheme, a behavioral scale similar to the Conners Rating Scales, before their gluten-free diet was started and 6 months later. Results: The overall score improves significantly as well as most of the ADHD-like symptomatology specific features (Bonferroni-corrected, paired-sample t tests). Conclusion: The data indicate that ADHD-like symptomatology is markedly overrepresented among untreated CD patients and that a gluten-free diet may improve symptoms significantly within a short period of time. The results of this study also suggest that CD should be included in the list of diseases associated with ADHD-like symptomatology. (Contains 1 table.)