Background- Cobblestone production is highly labor intensive and physically demanding workrnthat exposes workers for musculoskeletal disorders. Evidences on measuring exposure level arernlimited in this area. As a result studying the magnitude and factors incorporating the ergonomicrnhazard exposure level measurement is crucial.rnObjective- The main objective of the study is to assess the prevalence and associated factors ofrnwork related musculoskeletal disorders among cobble stone workers.rnMethods- Cross-sectional study was conducted from December 2016-June 2017 among cobblernstone workers in Addis Ababa with a sample size of 537 using Nordic muscoloskletal disorderrnassessmet questionnaire and 56 paicipants using quick exposure cheek ergonomic hazardrnassessment tool. The data were collected by interviewing participants by trained six datarncollectors and three supervisors. The data were entered and cleaned using epi info version 7 andrnimported to statistical package for social science software version 20 for analysis. The data werernanalyzed using descriptive statistical method for magnitude and using bivariate and multivariablernlogistic regression models to identify factors associatiated with work related musculoskeletalrndisorder.rnResults- A total of 512 respondents included in this study, with 95% response rate.Over all 12rnmonth prevalence 417(81.4%) of work related musculoskkletal disorder were obtained. Fromrndifferent body parts lower back is 65.5%, wrist 51.6%, shoulder 47.9% and neck 24.2% werernfound. Job stress (OR=1.75), working days (OR=3.38), awkward working posture (OR=3.29),rnlack of break time (OR=2.2) and ergonomic training (OR=2.9) found to be have statisticallyrnsignificant association with work related musculoskeltal disorder.The result obtained from quickrnexposure cheek reveals that exposure level of very high for back,high and very high for shoulderrnand wrist and moderate for neck.rnConclusion and recommendation- Work related musculoskletal disorder among cobblestonernworkers are characterized with very high prevalence with high and very high ergonomic hazardrnexposure level for majority of body parts. Work load, twisting bending position, lack of breakrnand lack of ergonomic training are factors for the development of work related musculoskletalrndisorders therefore ergonomic training mainly focusing on manual handling should be provided.