Background: Ramadan fasting for patients with type 1 DM put their physicians in challenge as it may increase the risk of both hyperglycemia and hypoglycemia. This study aimed: To assess safety of Ramadan fasting among patients with type 1 DM and to assess the impact of fasting on incidence of diabetic complications in those patients. Patients and Methods: This cohort study included 90 known diabetic patients who insist on fasting Ramadan, they were classified according to risk stratification of IDFDAR risk score into 3 groups; high and, moderate risk of type 1 and low risk of type2 DM, 30 patients in each group. All of them were subjected to full history taking, clinical examination, routine lab, HBA1c, In addition to SBGM during fasting and estimation of GFR at the start and end of fasting Results: The incidence of hypoglycemia was found to be higher in the high-risk group in comparison to both moderate and low risk groups, also higher in moderate risk group when compared to low risk group, p< 0.05 There was a statistically insignificant difference in the incidence of DKA between the three groups despite being numerically higher in the high-risk group, p>0.05. There was statistically significant decrease in eGFR only in high-risk group at the end of Ramadan Conclusion: Ramadan fasting in the high and moderate risk patients with type 1in our cohort was associated with increased risk of hypoglycemia &DKA and negatively affects the kidney function.in high risk group Keywords: Kidney Function, Ramadan Fasting, Type 1 Diabetes mellitus