Background: Iodine deficiency is the world's single greatest cause of preventable mental retardation in developing countries. The aim of this study was to evaluate the effect of nutrition education intervention about iodine deficiency disorders and iodized salt intake on mothers performance. A quasi-experimental design was used in this study. The study was conducted at six maternal and child health centers in Zagazig City (Shaybah Al-Nakariah, Shabanat, Bahnbay, Al- Nakhas, Shambara Al-Maimuna, and Al-Aslouji). Sampling: Sample composed of 125 mothers were selected randomly from maternal and child health centers. Three tools were used to collect the necessary data for achieving the study objective: An interviewing questionnaire to assess socio- demographic characteristics, knowledge about iodized salt and iodine deficiency disorders’ scale, attitude, and practices related to iodine. Results: all the mothers’ had got satisfactory knowledge, positive attitude and adequate practice (100%, 100%, & 99.2%) post intervention versus pre intervention( 6.4%, 20%, & 30.4%) respectively with highly statistically significant differences which continued 3 months later. Moreover, in a multivariate analysis, statistically significant independent positive predictors of the mothers’ practice scores related to iodine salt and iodine deficiency disorders were their intervention, education, income, knowledge score, and attitude score. Conclusion: This study revealed that the educational intervention was highly statistically significant positive effect on the studied mothers’ performance (knowledge, practice & attitudes). Therefore, it is recommended that educational nursing intervention about iodine deficiency disorders and iodized salt intake should be provided periodically and continually to all mothers attending MCH Centers by qualified health professionals