Background: Nutritional disease, any of the nutrient-related diseases and conditions that cause illness in children. Orphanages children are more prone to Nutritional disease. Aim: This study aimed to evaluate the effect of health educational program for orphanages children regarding prevention of nutritional diseases. Research design: A quasi experimental research design was used in this study (pre-post test). Setting: The study was conducted at two orphanage homes (social home care for males and social home care for females) at Benha City in Kalyubia Governorate. Sample: A convenience sample of children (60 child) according to certain criteria of inclusion (6:17 years). Tools: Two tools were used. (I): Was a structured interviewing questionnaire which consist of two parts: (A): Demographic characteristics of orphanages children. (B): Children's knowledge regarding nutrition and nutritional diseases. (II): Observe children's practices concerning nutrition. Results: 33.3% of studied children had good total knowledge pre implementation of the program which increased to 55% post program, 20% of studied children had satisfactory total practices level preprogram which increased to 80% post program. There was a positive highly statistically significant correlation between the studied children's total practices score and their total knowledge score pre and post program. Conclusion: Health educational program   had a positive effect on improving level of knowledge and practices of orphanages children regarding prevention of nutritional diseases. Recommendations: Continuous health education programs are needed for the prevention of nutritional diseases.