Work-related musculoskeletal disorders (WMSDs) resulting from ergonomic hazards are common in the United States. Recent data from the Bureau of Labor Statistics (BLS) indicate that in 2011, one third of occupational injuries and illnesses resulting in lost time from work were WMSDs. Based on data from the 2010 BLS Survey of Occupational Injuries and Illnesses, a higher rate of WMSDs resulting in lost time from work occurred in the Wholesale and Retail Trade (WRT) industry compared with most other industries. To assess trends and identify WRT subsectors and subgroups associated with high rates of WMSD workers' compensation claims, the Ohio Bureau of Workers' Compensation (OBWC) and CDC analyzed OBWC claims data for single-location WRT employers in Ohio for the period 2005-2009. From 2005 to 2009, the rate of WMSD claims declined from 86.3 to 52.8 per 10,000 employees. The three WRT industry subsectors with the highest rates of WMSD claims were Merchant Wholesalers, Nondurable Goods; Furniture and Home Furnishings Stores; and Merchant Wholesalers, Durable Goods. Within those three WRT subsectors, the highest rates of WMSD claims were noted in five subgroups: furniture stores and wholesalers of alcoholic beverages, groceries and related products, metal and minerals, and motor vehicle parts. Providing recommendations for WMSD prevention is particularly important for these WRT subgroups. OBWC is the largest of four state-run workers' compensation systems in the United States where the state is the sole provider of workers' compensation insurance. Data for OBWC-insured, single-location employers in the WRT industry were used for this report; subsectors and subsector groups were categorized according to the North American Industry Classification System (NAICS). With few exceptions, WMSD claims were defined according to BLS case definitions. Coded injury/illness diagnosis data and narrative text on causation were used to identify WMSD claims; a Bayesian auto-coding technique used both data elements to identify WMSDs by using a "training" and "testing" set of manually coded claims. The sensitivity and specificity of this auto-coding technique when applied to a test set were 0.90 and 0.98, respectively. Auto-coded WMSD claims were flagged for manual, expert review when the injury/illness diagnosis was not a WMSD. Lost-time claims for WMSDs were defined as claims resulting in more than 7 days away from work. To calculate incidence rates, OBWC claims data were linked with denominator data (number of employees) from the Ohio Department of Jobs and Family Services by federal employer identification numbers. Trends in rates were tested using Poisson regression analysis. Disallowed and dismissed claims were excluded from all analyses. In 2009, CDC identified 31,599 OBWC-insured, single-location employers in the WRT industry, employing at least 289,441 workers. Of those identified WRT employers, 13,930 (44%) were in the wholesale category of the industry. The proportion of all claims attributable to WMSDs was relatively stable at approximately 20% throughout 2005-2009; the proportion of WMSD lost-time claims decreased from 37.4% in 2005 to 31.8% in 2009 (p<0.05). During 2005-2009, the majority of claimants were men aged 25-54 years, who worked for employers with 11-249 employees. The greatest number of WMSD claims occurred in the WRT subsector Merchant Wholesalers, Durable Goods. The rate of WMSDs resulting in a claim or a lost-time claim decreased significantly from 2005 to 2009 for WRT industry employers overall but not for all WRT subsectors. Overall in the WRT industry, the respective rates of WMSD claims and lost-time WMSD claims per 10,000 employees decreased from 86.3 and 28.7 in 2005 to 52.8 and 14.1 in 2009. Employers with more employees tended to have higher rates of total and lost-time WMSD claims. During 2005-2009, lost-time WMSD claim rates per 10,000 employees for three WRT subsectors were among the highest five each year: Merchant Wholesalers, Nondurable Goods (29.2 in 2009); Furniture and Home Furnishings Stores (21.7); and Merchant Wholesalers, Durable Goods (15.5). The high lost-time WMSD rates in these three WRT subsectors were consistently attributable to high rates in five subgroups within the subsectors: wholesalers of alcoholic beverages (114.8 in 2009), grocery and related products (30.9), metal and minerals (28.0), and motor vehicle parts and supplies (25.4); and furniture stores (27.2).