Objectives:To compare the differences between the incidence of respiratory tract infections before and after performing Hajj and to identify the risk factors that may increase the prevalence of respiratory tract infections during Hajj.Methods: During the Hajj season of 1437H in Al Madinah, a prospective cohort study consisting of 566 pilgrim patients was admitted to ER in King Fahad Hospital (160 patients), Al Anssar (100), Bab Jebril Primary Health Clinic (70) and Al Safiah Primary Health Care (236). A face-to-face semi-structured questionnaire was given to each participant a week before and after the Hajj. Results: During the two-week examination period, 92% of patients suffered from respiratory symptoms. It was the first visit to the doctor with the same symptoms for 82.3% of pilgrims. The age group of a vast majority of the patients who participate in the study was 46-65 years. Findings indicate that 89.2% of participants had been in crowded places during the pilgrimage period. Also, 15.9% of participants were smokers, and 81.3% of them had a good ventilation in their residential places. The residential areas of participants (63.4%) were very far from any sources of air pollution. Besides, 82.2% of them did not use their personal belongings during the pilgrimage period.. Conclusion: Most pilgrim patients suffered from and shown respiratory symptoms during Hajj. The study noted a reduction in most risk factors which increase respiratory tract infections except the problem of overcrowding during the Hajj season, a problem that cannot be avoided during the pilgrimage to