Introduction:Psychological impact of Therapeutic Patient Education (TPE) for dialysis patients is rarely evaluated since the focus of many studies is on medical variables (i.e., adherence).Objectives:The aims of this study were: 1) to estimate the impact of a TPE program on knowledge, depression and anxiety, 2) to examine change in knowledge as a mediator of the effects of a TPE program on mental health.Method:This study was conducted in three hemodialysis units and comprised two groups: an experimental group with education and a control group with routine care. The program was based of 5 educative sessions. Knowledge, depressive and anxious symptoms were assessed with self-reported outcomes measured before and 3 months after the program.Results:The sample comprised 125 patients. Knowledge about vascular access and nutrition (p < 0.01) and depressive symptoms increased in the experimental group (p < 0.01). Analysis of mediation showed that changes in knowledge about vascular access were a significant mediator of the effects of the program on depressive symptoms (F = 4.90;p = 0.01).Discussion:Knowledge acquired during an educational program could lead to an emotional change. Improving knowledge often leads to an awareness of the risks that can modify the psychological state of patients by reminding them of their vulnerability. This study shows that it is required to be attentive to the way of transmitting knowledge. It’s necessary adapting this transmission to the needs of patients and promoting the acquisition of psychosocial competence too.Conclusion:This study shows that knowledge acquired during an educational program can lead to an emotional change in the short term. A long-term follow-up of the population should be interesting to observe these emotional effects.