Objectives. We examined rates of uninsurance among workers in the US health care workforce by health care industry subtype and workforce category. Methods. We used 2004 to 2006 National Health Interview Survey data to assess health insurance coverage rates. Multivariate logistic regression analyses were conducted to estimate the odds of uninsurance among health care workers by industry subtype. Results. Overall, 11% of the US health care workforce is uninsured. Ambulatory care workers were 3.1 times as likely as hospital workers (95% confidence interval [CI]=2.3, 4.3) to be uninsured, and residential care workers were 4.3 times as likely to be uninsured (95% CI=3.0, 6.1). Health service workers had 50% greater odds of being uninsured relative to workers in health diagnosing and treating occupations (odds ratio [OR]=1.5; 95% CI=1.0, 2.4). Conclusions. Because uninsurance leads to delays in seeking care, fewer prevention visits, and poorer health status, the fact that nearly 1 in 8 health care workers lacks insurance coverage is cause for concern.