OBJECTIVES: To evaluate the risk of injury associated with attention-deficit hyperactivity disorder (ADHD) using information from an employee database. METHODS: Using the MarketScan® Commercial Claims and Encounters Database from Thomson Reuters, patients aged 18 to 64 years and diagnosed with ADHD (N=31,752) were matched by similarity in demographics and data availability 3:1 to controls without ADHD (N=95,256) or 1:1 to controls diagnosed with depression (N=29,965). Patients with ADHD were also stratified into compliant (Medication Possession Ratio [MPR] ≥0.8; N=8654), partially compliant (0.3≤MPR<0.8; N=5233) and noncompliant (MPR<0.3; N=4007) cohorts. Risk of injury was compared between groups for January to December 2006. Multivariate analyses controlled for treatment differences between groups that remained after matching. RESULTS: Injury rates were higher in the ADHD group than in the non-ADHD control group (21.6% vs 15.7%, p<0.001) and depression group (21.4% vs. 20.5%, p=0.0085), and higher in the compliant group than in the partially compliant (22.8% vs 20.3, p=0.0004) and noncompliant (22.8% vs 17.8%, p<0.001) groups. In multivariate analyses, risk of injury was higher in the ADHD group than in the non-ADHD (1.3194 odds ratio [OR], p<0.01) and depression control groups (1.1263 OR, p<0.01) and higher in compliant and partially compliant patients than in noncompliant patients (1.2633 and 1.664 OR, respectively, p<0.01). Comorbid depression, anxiety and substance abuse predicted a higher risk of injury in the ADHD versus control groups (p<0.01) and in compliant/partially compliant patients versus noncompliant patients (p<0.01), with magnitude equal to or exceeding that of the ADHD group alone. CONCLUSIONS: Patients with ADHD had higher risk of injury than similarly matched patients without ADHD or with depression, suggesting important implications for workplace safety and liability.