Background: The impact of fasting during the month of Ramadan, practiced by adult Muslims, on glucose homeostasis has attracted much attention recently with view to understanding the metabolic price of fasting and to help plan rational management. The flash glucose monitoring (FGM) expressed as ambulatory glucose profiles (AGP) provides a minimally invasive yet comprehensive insight into blood glucose (BG) changes in relationship to various physiological and behavioral factors. Objectives: To investigate the BG homeostasis during Ramadan fasting in a group of individuals with different states of glucose tolerance. Methods: Eight individuals who were fasting during Ramadan were studied by FGM using the Abbott's FreeStyle® Libre™ system. They included individuals with normal glucose tolerance during pregnancy (1), prediabetes (2), postbariatric hypoglycemia (1) and type 2 diabetes mellitus (4). Results: In the normal pregnancy AGP's fluctuated minimally around meals with some asymptomatic low BG readings on prolonged fasting. In those with prediabetes, most of the daytime BG were within normal but there was a minimal post-prandial rises and some asymptomatic lower readings on prolonged fasting too. In the case of the patient with history of post-bariatric hypoglycemia, daytime fasting periods had perfectly stable normal BG. However, marked early postprandial hyperglycemia occurred in the evening followed by a short-lived symptomatic hypoglycemia. In the 4 patients with diabetes, AGP showed high glucose exposure, wide variation and marked instability after both traditional meals of dawn time (Suhor) and sunset (Iftar) particularly in the later. A variably slow downward trend throughout the day was observed. The differences in the AGP's reflected both biological and behavioral differences between patients within the general picture. AGP's before, during and after Ramadan in 3 patients revealed distinctly-different profiles reflecting the Middle Eastern meal pattern, Ramadan meal pattern and Eid feasting respectively. For patients these findings were discussed