Résumé : Background. To improve the provision of information to their radiotherapy patients, the authors examined whether the timing of given written information has an effect on anxiety and satisfaction. Methods. Two sources of information were used: 1) a booklet with a description of radiotherapy procedures and the sensations patients can experience; 2) teaching sheets with treatment-site-related information. 68 patients were randomized to a simultaneous-information group (n = 31) and a stepwise-information group (n = 37). The patients were being treated for cancers of the breast, lung, head, and neck or the pelvic region. The authors analyzed the impacts of several variables on patient learning, including anxiety, age, gender, support, referral, stage of illness, and diagnosis. Assessments were recorded before the simulation procedure and during the second and last weeks of treatment. Results. The stepwise-information group was significantly less anxious before simulation (p = 0.02) and more satisfied (p = 0.001). Of the variables studied, only the support variable was associated with high state anxiety (p < 0.0001). Conclusions. Provision of patient information in a stepwise format leads to less treatment-related anxiety and greater patient satisfaction among radiation therapy patient undergoing simulation.