BACKGROUND: Fatigue is reported by many adults at the moment of diagnosis of coeliac disease and during follow-up. AIM: To evaluate the prevalence, characteristics and associations of fatigue in adult coeliac disease patients. METHODS: The investigated sample comprised adults from Campania, Italy. A total of 130 coeliac disease patients were consecutively recruited in both treated (59 on gluten-free diet) and untreated conditions (71 on normal diet). The control group was made up of 80 healthy controls. Coeliac disease patients and healthy controls underwent laboratory tests, a set of questionnaires for studying fatigue: visual analogue scale for fatigue, chronic fatigue syndrome questionnaire, fatigue severity scale and a modified version of the Zung self-rating depression scale. RESULTS: Coeliac disease patients showed a significantly lower body mass index than controls (P = 0.0001), lower serum iron (P = 0.04). The entire cohort of coeliac disease patients reported greater modified version of the Zung self-rating depression scale score (P = 0.001), greater visual analogue scale for fatigue score (P = 0.0001) and greater chronic fatigue syndrome questionnaire score (P = 0.0001) compared with healthy controls. Coeliac disease patients on a gluten-free diet had a significantly higher modified version of the Zung self-rating depression scale score than coeliacs on a normal diet (P = 0.001). The prevalence of pathological modified version of the Zung self-rating depression scale score was 17% in all coeliac disease patients and 0% in healthy controls. A significant correlation was found between modified version of the Zung self-rating depression scale score and fatigue scale scores in coeliacs on a normal diet. Presence/absence of gastrointestinal symptoms did not show any significant correlation with modified version of the Zung self-rating depression scale score and fatigue scale scores. In coeliacs on a gluten-free diet, modified version of the Zung self-rating depression scale and fatigue scales scores did not significantly differ from coeliacs on a normal diet and were not related to dietetic compliance. CONCLUSION: In coeliacs, fatigue is a common finding, which ameliorates with the gluten-free diet and is strictly correlated to depression although coeliacs on a gluten-free diet showed more frequent and more severe depression symptoms than coeliacs on a normal diet.