BACKGROUND The Hajj Ceremony, the largest annual gathering in the world, is the most important life event for any Muslim. This study was designed to evaluate the incidence of stroke among Iranian pilgrims during the Hajj ceremony. METHODS We ascertained all cases of stroke occurring in a population of 92,974 Iranian pilgrims between November 27, 2007 and January 12, 2008. Incidence and risk factors of the first ever stroke in Hajj pilgrims were compared, within the same time frame, to those of the Mashhad residents, the second largest city in Iran. Data for the latter group were extracted from the Mashhad Stroke Incidence Study (MSIS) database. RESULTS During the study period, 17 first-ever strokes occurred in the Hajj pilgrims and 40 first-ever stroke strokes occurred in the MSIS group. Overall, the adjusted incidence rate of first ever stroke in the Hajj cohort was lower than that of the MSIS population (9 vs. 16 per 100,000). For age- and gender-specific subgroups, the Hajj stroke crude rates were in general similar to or lower than the general population of Mashhad, Iran, with the exception of women aged 35 to 44 years and aged >75 years who were at greater risk of having first-ever stroke than the non-pilgrims of the same age. CONCLUSION The first ever stroke rate among Iranian Hajj pilgrims was lower than that of the general population in Mashhad, Iran, except for females 35-44 or more than 75 years old. The number of events occurring during the Hajj suggests that Islamic countries should consider designing preventive and screening programs for pilgrims.