The main reason for insufficient control of celiac disease is non-adherence to the gluten-free diet (GFD), whether voluntary or involuntary. In children, involuntary exposures are common (canteens, snacks, restaurants). There are no evidence-based recommendations regarding the best way to follow up with patients and assess adherence to the diet. Monitoring of celiac disease is traditionally based on IgA anti-transglutaminase (IgA anti-tTG) serology, but it reflects a delayed immune response and does not detect occasional exposures. Numerous studies conducted outside of France seem to highlight the usefulness of measuring gluten immunogenic peptides (GIP), compared to the current tools used. Measuring GIP in urine, which is non-invasive and can be performed regularly, could allow for earlier and more objective detection of recent gluten exposure, particularly inadvertent exposure, even before symptoms appear. Furthermore, it could serve as a complementary test for patients who continue to show symptoms or positive serology despite a reported well-followed GFD. In such situations, the use of control esophagogastroduodenoscopy (EGD) with jejunal biopsies could be reconsidered in the event of positive urinary GIP. This is the first study conducted in France on the usefulness of urinary measurement of immunogenic gluten peptides in the follow-up of pediatric celiac patients.