Objectives: Semicircular lipoatrophy (SL) is an emerging occupational pathology. Its etiology is poorly understood. We intend to establish the probable risk factors and estimate the relative risk. Methods: A case-control study was performed. Our company had 55 diagnosed cases. As controls, we used the 3 closest healthy coworkers to each case. We calculated the chi square, odds ratio and logistic regression for different exposures, during the 3 years from September 2007 to August 2010. Results: There was 100% participation for the cases and 70.9% for the controls (ratio 1 : 2.1 case-control). The only risk variables found were female gender ( p <0.02) and exposure to leaning on the edge of a table ( p <0.01). In addition, a breakdown by sex objectifies a much stronger association with leaning on the edge of a table in women ( p <0.01) than men ( p 0.67). Conclusions: Female gender and leaning on the edge of a table (repeated microtrauma), especially in women, are risk factors for development of SL. Other variables seem to be confounding factors associated with female gender. There were no SL cases showing statistically significant relations with history of cancer or autoimmune diseases. There was also no significance with regard to wearing jeans. There is therefore a new risk for office staff in addition to the more traditional disorders (musculoskeletal, ocular, and psychosocial). Further studies are necessary to evaluate what we consider an underdiagnosed condition, since there is a large percentage of people that are potentially exposed and we found very little information in the literature on the matter.(J Occup Health 2013; 55: 149–157)