Purpose: This study was constructed in order to examine factors that influence work-related musculoskeletal disease (WMSD) approvals and current status according to the company size. Method: This is a descriptive study that utilized Industrial Accident Compensation Claim Data. Workplaces with over 35,811 workers derived from the 2012 claim data, which comprised approximately 91.5%, were selected for this study. Then workplaces were divided into three groups according to the number of workers: less than 5, 5~299, and 300 and over. Results: Since 2008, the number of small sized workplaces has increased. The 2012 data showed that 32.5% of workers at small sized workplace had WMSD. However, workplaces with 5~299 workers showed WMSD approval rate of 60%. Of note most WMSD approved workers were employed by manufacturing and construction companies, regardless of the workplace size. Most of them were engaged in elementary tasks. The days of medical treatment at OPD and IPD were most prevalent among workers at the largest workplaces. Conclusions: It is certain from this study that WMSD has been polarized by the company size. More policy attention should be paid to the WMSD status of workers at small sized workplaces which usually do not have their own health office.