Objective: This study sought to assess the effect of reading augmented reality (AR) books on salivary cortisol levels in hospitalized pediatric patients compared to reading a standard children's book. Methods: This was a randomized, two-period, cross-over trial in hospitalized children aged 7–11 years. AR books currently in the market were used as intervention. Complete block randomization was used to randomize the order of the intervention. Children allocated to the ‘AR-first’ group received the book, a tablet and were left to interact independently with the technology for an hour. After a 48 -h wash-out period, children received a standard book. ‘Standard-book-first’ group received only the standard book and after wash-out received the tablet and the AR book. Salivary cortisol and a validated visual analogue scale (VAS) for psychological stress were assessed at the beginning ...