BACKGROUND Celiac disease is a common disorder but there are few studies comparing the clinical features of the disease in adults, adolescents and children. METHODS Demographic and clinical characteristics of all patients with celiac disease referred to the Celiac Clinic were evaluated and compared in different age groups. RESULTS Of 3416 participants, 473 patients were included. 302 (63.8%) were women and 171 (36.2%) were men. Overall, 325 (68.7%) and 411 (86.9%) patients had gastrointestinal (GI) and non-GI manifestations, respectively. The most common symptom in adults was psychiatric problems (66.5%), while abdominal discomfort was the most common symptom in adolescents (45.2%) and children (53.8%). According to age groups, GI manifestations were seen in 79 (66.4%), 119 (59.8%), and 127 (81.9%) children, adolescents, and adults, respectively. Adults had significantly more GI manifestations than the other groups (PR 1.167; 95% CI: 1.094- 1.244; p < 0.001). Non-GI manifestations were seen in 90 (75.6%), 174 (87.4%), and 147 (94.8%) children, adolescents, and adults, respectively. Adults had significantly more non-GI manifestations than the other groups (PR 1.112; 95% CI: 1.060-1.168; p < 0.001). CONCLUSION Our study showed that there were significant differences in the clinical features of celiac disease between the different age groups. Considering these results may help plan for future studies.