Introduction: Road traffic injuries (RTIs) are the most serious health issue in the world and the main cause of death after the first year of birth. Environmental factors are among the most important and effective aspects of RTIs occurrences and their human consequences. Aim: This study aimed to identify the environmental factors associated with road traffic accidents (RTAs) in Ilam province. Methods: All crash data in Ilam province in 2012 were investigated. RTIs data was collected using COM 114 form which included some human, environmental and vehicle related factors. Through Chi-Square test and logistic regression model, the association between environmental factors and RTIs was examined. For all statistical analyses we used the package Stata 13.1. Results: A total of 2314 traffic accidents were investigated. The highest 1659 (72.3%) and lowest 19 (0.83%) frequency of RTAs occurred during day and sunrise respectively. The majority of RTAs took place in July and September. The maximum number of RTAs was when the day was clear (91.7%) 2103 and the minimum when it was cloudy (3.5%) 81. A significant relationship was found between fatal RTAs and factors such as; the sort of the road, the hindered visibility, the location of the accident, the accidents place, the climate, and lighting of the day (P
Key words: Traffic Accidents, Environmental Exposure, RTIs, Risk Factors, Injury, Iran.