Introduction: globally there is an increase of Type 1 diabetes among children. Poorly controlled Type1 diabetes is associated with the complication. Although medication adherence is important for diabetic children to prevent disease-related complications and improve quality of life, the rate of children adherence to therapeutic regimen is somewhat disturbing. Hence, this study aimed to assess factors affecting adherence toward therapeutic regimen among children with type 1 Diabetes Mellitus. Design: Descriptive exploratory design. Setting: This study was conducted at Diabetic Outpatient Clinic in Children's Hospital. Sampling: A purposive sample comprised of 200 children with type 1 Diabetes Mellitus. Tools of data collection: The data was collected using the following Tools: Ι-Interview questionnaire sheet. It consists of 4 parts: Part I: bio-sociodemographic Characteristics of children. Part II: assessing the level of knowledge regarding DM, complications, and therapeutic regimen. Part III: Adherence of children to therapeutic regimen. Part V: assessing the level of adherence and factors affecting children adherence toward therapeutic regimen. Results: This study revealed that more than two thirds 78% were satisfactory. Regarding p-value knowledge about therapeutic regimen was highly significant < 0.001*. Also, this study showed that hypoglycemia and hyperglycemia adherence were more than two thirds (80.3%, 76.7%) respectively and p-value were highly significant to both. According to Medication intake adherence were 85.7% and highly significant. Regarding Follow up adherence were 73.3% and highly significant. As regards factors affecting children adherence toward their therapeutic regimen, these showed that physical factors were 90% followed by Financial factors were 79%. Conclusion: it was concluded that the factors affecting children adherence toward their therapeutic regimen related to physical factors and financial factors were large percent. While, Psychological factors, Lack of knowledge and Lack of social support were small percent. Recommendation: Continuous health teaching to children with type 1 diabetes and their caregivers regarding diabetes, its complication and management.