The risks of Ramadan fasting on blood pressure (BP) in patients with adrenal insufficiency are unknown. This study aimed to evaluate the levels of BP and particularly the risk for hypotension during a fasting day compared with a nonfasting day in patients with corticotrope deficiency. A prospective case-crossover study on 28 patients with known and treated corticotrope deficiency who were fasting the month of Ramadan. Clinical (eating and sleeping habits, abnormal symptoms, weight, height, and BP) and paraclinical (creatinine, sodium, and cortisol) data were collected. Patients had a 24 h ambulatory BP monitoring during a Ramadan fasting day then again during a nonfasting day. The data of 25 patients were analyzed; 20 women, median age: 40 years (IQR, 22.5-45.5), median duration of the disease: 6 years (IQR, 2.5-12). The prevalence of hypotension did not differ between the fasting day and the nonfasting day. Hour by hour BP levels comparison showed that both systolic and diastolic BP were significantly lower at 2.00 p.m. during fasting. BP variability was significantly lower during the fasting period compared with the same period during the nonfasting day. Fasting was not associated with an increased risk for hypotension in patients with known and treated corticotrope deficiency.