Background: Type 1 Diabetes Mellitus is one of the most common chronic health conditions in youth. Sleep is a crucial determinant of psychological, emotional, and physical health. There are evidences suggest that Type 1 Diabetes Mellitus may be associated with sleep disorders. Objective: Our aim is to study sleep architecture in children with Diabetes Mellitus Type 1, by using polysomnography and correlating the findings to glycemic state. Methods: Forty children were included in this study, divided into two groups: twenty diabetic patients and twenty healthy volunteers. All children were subjected to thorough clinical assessment, and polysomnography. Diabetic children were also subjected to the random blood sugar and HbA1c. Result: the diabetic group showedstatistically significant difference in the lighter sleep (N1 stage) (P value = 0.001) and respiratory parameters (average oxygen saturation and lowest oxygen saturation) (P values = 0.018) in comparison to the control group. However, no statistically significant difference was found on the deep sleep (N2, N3 & REM), Apnea Hypopnea index or snoring. Conclusion: Polysomnography can give valuable information helping to detect the effect of Type 1 Diabetes Mellitus on increasing the lighter sleep (N1 stage) and decreasing oxygen saturation in children with Type 1 Diabetes Mellitus.