Objectives: Companies that understand the collective health risks of their employees, as well as worker productivity as it relates to health risks can provide more effective and necessary interventions. Health Risk Assessments (HRAs) are an important source of information for understanding overall health risks of a company’s employees. However, HRA data tend to represent only a subset of employees, thereby providing employers an incomplete picture of employee health risks. The current study identifies the representativeness of those completing a worksite HRA by selected demographics, health care costs, and health risks in a large US company. Material and Methods: A retrospective analysis of employees in a large US company during 2017–2019, with statistically significant results reported, adjusted for sex, age, and year. Results: The percentage of employees completing the HRA increased from 23.9% in 2017 to 28.4% in 2018 to 32.3% in 2019. These employees were more likely women, middle aged, have lower health care costs, remain employed from year to year, and have better health behaviors and biometric scores. If all employees looked like employees completing the HRA, total medical costs would be 17% lower. If all employees looked like employees completing the HRA who had a health perception rating (1–10 [excellent]) of 7–8 (57.4%) or 9–10 (25.2%) vs. 1–6, total medical costs would be 21.9% and 25.6% lower, respectively. Conclusions: A minority of employees completed the worksite HRA. Basing overall employee health risks on the HRA underestimates health risks and can result in a poorly representative health intervention program. Int J Occup Med Environ Health. 2022;35(4):449–57