Diabetes is a global health problem. This is a slow killer with no known cure. However, proper detection and timely treatment can reduce complications. Clinical path is the best way to treat diabetic children. Aim of the study was to determine the effect of implementing clinical pathway on nursing care for children with type one diabetes mellitus suffering from hyperglycemia. Setting: The study was conducted at the department of endocrinology, Assiut University Children's Hospital. Method: Quasi-experimental research design was utilized in this study, A convenient sample of (40) nurses and all the available children with diabetes mellitus (40 children). Tools: Used four tools. Tool I: Background information form: It composed of three parts, demographic characteristics of studied nurses, demographic characteristics of the studied children, clinical data of studied children. Tool II: A nurse's knowledge consists of two parts: Nurses' knowledge of juvenile diabetes and Nurses` knowledge about nursing care of children with type one diabetes. Tool III: Clinical pathway of care checklist. Tool IV: Children' medical outcomes assessment form. Results: There was a statistical significance differences in nurse's knowledge and practices before and after using clinical pathway. Conclusion: There were an improvement on nurses' knowledge, practice and nursing care of children with type one diabetes suffering from hyperglycemia after implementing clinical pathway and it is effective in improving children' clinical outcomes. Recommendations: Clinical approaches to caring for children with typed one diabetes should be applied to children with diabetes in a variety of settings.