Complicated celiac disease (CCD) is a rare but severe condition with a poor prognosis. Guidelines recommend use of capsule endoscopy (CE) to explore the small bowel (SB), followed by a double-balloon enteroscopy (DBE) in selected cases with suspected CCD. Our study aims to evaluate the diagnostic yield of CE and DBE in identifying and monitoring CCD.Consecutive suspected CCD patients were prospectively enrolled to undergo CE and/or DBE in the presence of persistent symptoms despite gluten-free diet (GFD), increased anti-transglutaminase antibodies titer, lack of adherence to GFD and CCD follow-up. The diagnostic yields (DY) of CE and DBE were calculated. The incidence of neoplastic complications and mortality were assessed.In total, 130 patients (97 females, age 49±16 years) underwent 151 CE and 23 DBE. The DY of CE was 46%. Patients age >50 years (at CE examination or at CD diagnosis) with a disease duration <5 years were at higher risk of positive CE (RR 1.6, 1.7 and 1.5 respectively, p<0.05) than their counterparts. Up to 40% of SB lesions were unreachable by upper endoscopy. At the end of the diagnostic work-up, 25 patients with pre-malignant/malignant lesions were identified: 12 type-1 refractory CD (RCD-1), 7 type-2 RCD (RCD-2), 6 enteropathy-associated T-cell lymphoma (EATL). Six patients (2 RCD-2 and 4 EATL) died.In case of suspected CCD, CE should be the first-line approach to detect complications and to identify patients deserving DBE. Older and symptomatic patients with suspected CCD deserve a careful evaluation of small bowel especially during the first years after CD diagnosis.