Repetitive strain injury (RSI), also known as cumulative trauma disorder, implies that an injury exists and was caused by repetitive strain, but both implications are debatable. Ulnar neuropathy at the elbow (UNE), also known as cubital tunnel syndrome, is the second most common upper extremity compression neuropathy (after carpal tunnel syndrome). This article examines one particular aspect of the RSI debate: Is there scientific evidence to support a causal relationship between UNE and repetitive elbow flexion and extension in the workplace? The authors extensively searched published articles, books, and federal task force publications to look for evidence supporting a causal relationship between UNE and RSI. This included a literature review followed by a study of pertinent review articles, bibliographies, national task force reports related to musculoskeletal problems in the workplace, and relevant case reports. In brief, after extensive searches the authors found no credible medical literature to support a causal relationship between RSI and UNE. Case reports and cadaver studies provide tenuous support for causation of UNE by high-force activities such as pitching in baseball. The only prospective study that systematically assessed any causal relationship between RSI and UNE showed there is none. This article includes a three-page Feature Companion, “Rating Guidance: Ulnar Neuropathy,” that identifies common errors and provides an example rating report.