Objective To compare the health-related quality-of-life (HRQoL) of children with screening-detected coeliac disease (CD), before they learned of their diagnosis, with that of children without CD and in those previously diagnosed with CD. Methods In a cross-sectional CD screening study (‘ETICS’: Exploring the Iceberg of Coeliacs in Sweden), of 10,041 Swedish 12-year-olds invited, 7567 (75%) consented to participate, and 7208 (72%) children without previously diagnosed CD had serological markers analysed. Before the screening results were known, 7218 children (72%) and 6524 of their parents (65%) answered questionnaires. Questionnaires included the Swedish child-friendly pilot version of the EQ-5D instrument and proxy version of the EQ-5D instrument, which are generic tools used to describe HRQoL. Results We found no significant difference in HRQoL between the groups of children with screening-detected CD, without CD, and those previously diagnosed with CD. Conclusion The HRQoL reported by 12-year-olds with screening-detected CD, before they learned of their diagnosis, was not worse than that of the children without CD or those previously diagnosed with CD. Thus, mass screening for CD should not be justified on the basis that children with unrecognized CD have a poor HRQoL. However, because these children rated their HRQoL before diagnosis and treatment, they may not have recognized or perceived symptoms as severe enough to seek medical attention which demonstrates how difficult clinical/active case finding can be. Mass screening may still, therefore, be considered if the aim is early detection and prevention of future complications.