To review how commonly do diabetic Muslims fast, how safe is it to fast, who should not fast, and what is the optimal therapeutic regimen during Ramadan. Methods: Articles were identified from a Medline search on 19 Nov 2010 using MESH terms “diabetes mellitus”, “Islam” and “fasting” for articles from 1979 to date. Hand search of references of review articles was also done. Randomized controlled and observational trials were shortlisted and critically appraised. Results: 15 articles were shortlisted for review. Fasting is common among Muslim type 2 diabetics and to a lesser extent for type 1 diabetics. Fasting is generally safe for type 2 diabetics without complications. Hardly any evidence exists on the safety of fasting for high risk patients. There is some evidence that switching from soluble insulin to insulin Lispro may be beneficial. There is also some evidence that pioglitazone may improve glycaemia in poorly controlled diabetics without increasing the risk of hypoglycaemia. Conclusion: Fasting may be done safely for selected diabetic patients in Ramadan. Treatment should be individualized.