Background: Nowadays, worldwide road traffic-related injuries, disabilities, and deaths are becoming a major public health threat. It is projected that by the year 2020, road traffic injuries are becoming the thirdlargest cause of disabilities in the world. More than 85% of the world's road fatalities are attributed to developing countries. Objective: This study aims to assess the prevalence of road traffic accident and associated factors among drivers of three and four-wheeled vehicles in East Wollega, Western Ethiopia 2017. Methodology: A cross-sectional study design was employed to gather information from 400 drivers of three and four-wheeled vehicles from February to March 2017. Data were entered into Epi info version 3.5.3, cleaned and analyzed using SPSS version 20. Bivariate and multivariate analyses were used to examine the association between dependent and independent variables. Statistical significance was declared at P-value 0.05. Result: The data were collected from 400 drivers making response rate of 94.6%. The mean age of the study participants was 28.4±4.3. About one third (33%) of the drivers encountered an accident in the last one year. Living in urban (AOR=0.29, 95% CI [.09-.095]), Age of respondents 25-34 years (AOR=2.58, 95 %CI [1.46-4.54]) & >=35 years (AOR=2.53, 95%CI [1.20-5.33], sometimes angry(AOR=0.40, 95% CI [0.21-0.77], don't angry at all (AOR=0.26, 95% CI [0.11-0.60], Mobile speaking habit while driving (AOR=1.67, 95% CI [1.21-2.74]), driving on straight road (AOR=0.5, 95% CI [0.31-0.78]) and being penalized (AOR= 1.89, 95% CI [1.18-3.06],) were among factors associated with road traffic accident. Conclusion: The prevalence of road traffic accident revealed in this study is a public health significance. The most perceived cause of road traffic accidents mentioned was an overcrowded road which is shared by drivers, pedestrians, and animals. Therefore, it is better if the zonal and town transport agency office work on the management of road traffic utilization and continuously follow the driver's behaviors.