These guidelines aim to provide evidence-based practical guidance for the management of patients with heat illnesses during Hajj, particularly life-threatening heatstroke. The guidelines include recommendations that target adults who are at risk of developing heat illnesses during Hajj especially the elderly and those with chronic illnesses. These recommendations are not intended to replace a clinician’s judgement when he or she is presented with a patient’s unique clinical presentation. However, most of these recommendations are appropriate for patients with heat illnesses either in and/or outside hospital settings.