INTRODUCTION: Fasting is one of the five basic obligations of Islam. Muslims fast during the month of Ramadan according to the lunar calendar. Fasting during Ramadan involves abstinence from food and drinks from sunrise to sunset. The present study investigated the effect of fasting during Ramadan in patients who presented to emergency departments. Results of this study may guide healthcare authorities in countries that provide health services to Muslim communities because of increased migration. MATeRIAL AND MeThODS: This is the first prospective multicentre study to examine emergency department applications for Ramadan. The study was performed between 05.26.2017 and 06.24.2017. Patients were classified according to cardiopulmonary complaints, trauma-associated complaints, neurological complaints, gastrointestinal complaints, headache, renal colic, upper respiratory tract complaints, and malaise. Vital signs, age, gender, presentation type, complaint type, hospital stay duration, requested laboratory examination, radiological examination, treatment outcomes, application time, smoking status, and fasting status of the study patients were recorded by using a questionnaire. ReSULTS: Fasting and non-fasting patients showed a significant difference with respect to presentation type, gastrointestinal complaints, upper respiratory tract complaints, hospitalization status, requested radiological and biochemical examinations, hospitalization duration, and application time (p < 0.05). CONCLUSIONS: To the authors' knowledge, the present study is the first to compare the complaints of fasting and non-fasting patients during Ramadan. The authors feel that this study is superior to several previous studies because it has been performed using a different perspective and provides more accurate and objective data than those reported in previous studies.