Background: Walking in green areas in hospitals are crucial to patients' health and well-being, green areas have beneficial impact on people's health and wellbeing. It is supposed that residence in green spaces nearby in combination with physical activity could lower blood glucose levels. Purpose: To assess the effect of brisk walking exercise in green space on blood glucose level among children with type 1 diabetes mellitus. Setting: Pediatric Department and Hospital Park in Shebin El kom Teaching Hospital, Menoufia Governorate. Instruments: Four instruments were utilized (Diabetic children's assessment, State Trait Anxiety Inventory for Children (STAIC), Sleep Disturbance Scale for Children (SDSC) and Adherence to diabetes care recommendations. Results: Mean score of fasting blood sugar in the study group decreased in the seventh day (106.77 ± 19.13) compared to the first day (130.37 ± 10.91). Also, there was significant improvement in the mean score of anxiety, sleep disturbance and child's adherence to care recommendation in study group compared to control group on post intervention. Conclusion: Children with diabetes mellitus who perform brisk walking exercise in green spaces had lower fasting blood glucose value, decreased length of hospitalization, lower level of anxiety, reduced sleep disturbance and more adherence to care recommendations. Recommendations: Children with type1 diabetes should make brisk walking in green areas.