Background & Aim: Mucositis is one of the most common side effects of chemotherapy that affects the acceptance and continuation of treatment by the patient, Therefore, recognition of this complication and ways of preventing it in improving the course of treatment and preventing repeated hospitalization and survival these patients are helpful, The aim of this study was to determine the effect of maternal empowerment training on the prevention of oral mucosal inflammation in children under chemotherapy, Materials & Method: This clinical trial study was performed on 40 mothers of children aged 1 to 12 years old under chemotherapy in two case and control groups at Tehran Bahrami Hospital in 1396, Mothers who were admitted to the study were selected randomly and randomly assigned to 20 subjects in the case group and 20 subjects in the control group, In the case group, the necessary training was done in 5 steps according to the clinical guidelines in accordance with the empowerment model in 4 steps, The instruments used in this study were demographic information questionnaire and a checklist of signs and symptoms of acute and common complications of chemotherapy in children, The reliability of the checklist was considered to be 0, 88 using Cronbach's alpha, Data were collected from a researcher-made checklist in 3 stages of the second, fourth and eighth weeks after the intervention, Data were analyzed using SPSS 22, Results: The mean of the complication of oral mucosal inflammation after the intervention in the case group was less than the control group, The mean incidence of oral mucosal inflammation before intervention, second, fourth and eighth weeks after intervention was 1, 55 ± 1, 73, 0, 27 ± 1, 32, 0, 23 ± 1, 57, 0, 18 ± 1, 55, The results of Cochran test showed a significant reduction in the incidence of oral mucosal inflammation in the post-intervention period (P<0, 05), There was no significant difference in the incidence of oral mucosal inflammation in the control group before and after the intervention (P>0, 05) ) Also, the comparison of the case and control groups with regard to the incidence of oral mucosal inflammation showed that the oral mucosal inflammation in the case group was less than the control group, Conclusion: Empowerment program can help mothers to discover reality, increase their knowledge and ability, skills and critical thinking, thus preventing the complication of oral mucosal inflammation in children undergoing chemotherapy and have a significant role in self-care independently, , It can be used in other chronic diseases of children,