Background and aims; Ramadan is one of the five pillars of the Islamic religion. Fasting in the month of Ramadan is obligatory for all healthy adults Muslims. The physicians, as well as religious authorities strictly prohibit Muslim patients from fasting during the month of Ramadan. Regardless of exemption from this religious duty, some Muslim patients prefer fasting. The studies conducted on the effects of Ramadan fasting on cardiovascular disease, diabetes and chronic kidney disease and its safety are inconsistent; that’s why this review was aimed to evaluate whether Ramadan fasting is safe for them or not? Methods; A thorough search was done on electronic databases like Google Scholar, Embase, Scopus, MEDLINE,

Web of Science and Global health. Relevant articles were included in this study. The randomized and non- randomized trials, observational studies like case-control, cohort, and cross-sectional studies conducted

between 2009 and 2020 were included in this review. Results; based on the available literature, Ramadan fasting plays an important role in regulating human health. Fasting is not only beneficial for healthy individuals but for diseased individuals as well. Ramadan fasting significantly improves blood pressure, biomarkers of cardiometabolic risk, regulate inflammation, reduces weight, glycemic control and improves lipid profile. It has a positive impact on both type 1 and type 2 diabetes. Educating diabetic patients before the month of Ramadan can significantly reduce severe hyperglycemia and hypoglycemia. Grade 2-4 chronic kidney patients have no significant deterioration in the renal function who fast for the whole month of Ramadan. Conclusion; Available evidence suggest that Ramadan fasting may be safe for high-risk population i-e cardiovascular, diabetes and chronic kidney disease patients. However, for any definitive conclusions, more robust trials are required.