Road traffic crashes have a significant impact on social, economic and public health sectors in Ethiopia.rnGlobally, close to 1.35 million peoples die from road traffic crashes each year. Of these, on average,28% ofrnroad traffic death accounted for two and three-wheelers worldwide. These figures indicate that two andrnthree-wheelers death occurs more than a quarter of all road traffic crashes. In South Omo, motorcycles arernoften used for personal and commercial transport and gradually leads to different crashes, which deservesrnmore attention. The main objective of this study is to assess the magnitude and factors associated withrnmotorcycle crashes in the south Omo zone, Ethiopia. Both primary and secondary data sources were used.rnFour-year police-reported crash data included reports from (January 2014 to December 2017) aboutrnmotorcycle crashes was conducted from records of four police stations of south Omo zone and standardrnquestionnaire were require an in-depth understanding of the problems. First, descriptive statistics were usedrnby using frequency distribution and percentages. Multinomial logistic regression model and one-wayrnanalysis of variance (ANOVA) were done using SPSS software which was used to analyses secondary andrnprimary data respectively. The results indicate that a total of two hundred six motorcycle crashes have beenrnregistered in four police stations throughout the studied are from (January 2014 to December 2017).rnAmong these,36(17.5%) was fatal,88(42.7%) were serious injuries,52(25.2%) were slight injuries andrn30(14.6%) were caused by property damages. The gender proportion of motorcycle crashes were happenedrnby male riders only. The result of multinomial logistic regression model reveals that, severity ofrnmotorcycle crash increase with riders age of below 18 and between 31-50;low education level(5 to 8);rninsufficient riding experience(over 2 to 5); owners of motorcycle; long service year of motorcycle(over 5 torn10) and motorcycle with sudden mechanical problems are the main determinant factors for the occurrencernof motorcycle crashes. Almost, the highest number of motorcycles are legally registered. But, some ofrnthem are unregistered and the impact would be the severity of the crash which might be worst. In addition,rnthe result from the participants or motorcycle riders in this study respond shows that, of the total,37.9% ofrnmotorcycle riders are not wearing safety helmets. Moreover, the main factors that contribute to thernoccurrence of motorcycle crashes are human factors 266(68.6%), Vehicular (motorcycle) factor 36(9.3%),rnenvironmental factor 44(11.3%) and the other like enforcement of legislation and regulation 42(10.8%) arernother factors to the occurrence of motorcycle crashes.rnBased on the study, among others, the most important factors for motorcycle crashes were failure to givernpriority for pedestrians, careless riding, over speeding and violating traffic rules. Besides, loss of control ofrnmotorcycle and collision while overtaking other road users were the other most risk factors. Generally, thernproblem was steadily increasing in the study area over this period of time and needs critical remedialrnmeasurements. Though, the concerned policymakers may need to consider those mentioned factors;rnensuring that motorcycle riders obey traffic rules, making sure that the riders are properly training beforernriding and enforcing the speed limit appear to be the most critical parts of necessary measurements.