Heat-related illnesses (HRIs), such as heatstroke (HS) and heat exhaustion (HE), are common complications during Hajj pilgrims. The Saudi Ministry of Health (MoH) developed guidelines on the management of HRIs to ensure the safety of all pilgrims. This study aimed to assess healthcare workers’ (HCWs) adherence to the updated national guidelines regarding pre-hospital and in-hospital management of HRIs. This was a cross-sectional study using a questionnaire based on the updated HRI management interim guidelines for the Hajj season. Overall, compliance with HE guidelines scored 5.5 out of 10 for basic management and 4.7 out of 10 for advanced management. Medical staff showed an average to above average adherence to pre-hospital HS management, including pre-hospital considerations (7.2), recognition of HS (8.1), case assessment (7.7), stabilizing airway, breathing, and circulation (8.7), and cooling (5). The overall compliance to in-hospital guidelines for HS management were all above average, except for special conditions (4.3). In conclusion, this survey may facilitate the evaluation of the adherence to Saudi HRIs guidelines by comparing annual levels of compliance. These survey results may serve as a tool for the Saudi MoH to develop further recommendations and actions.