This study characterized and assessed self-reported levels of compliance with universal precautions (UP) among hospital-based physicians, and determined significant factors associated with both compliance and noncompliance. The physicians (n = 322) were a subgroup of a larger study population of hospital-based health care workers recruited from three geographically distinct locations (n = 1746), and were surveyed using a detailed confidential questionnaire that assessed personal, work-related, and organizational factors. Compliance with UP was measured through 11 items that examined how often physicians followed specific recommended work practices. Compliance was found to vary among the 11 items: they were high for certain activities (eg, glove use, 94%; disposal of sharps, 92%) and low for others (eg, wearing protective clothing, 55%; not recapping needles, 56%). Compliance with all items was low (31% to 38%). Stepwise logistic regression revealed that noncompliant physicians were likely to be age 37 or older, to report high work stress, and to perceive a conflict of interest between providing patient care and protecting themselves. Compliant physicians were more likely to be knowledgeable and to have been trained in universal precautions, to perceive protective measures as being effective, and to perceive an organizational commitment to safety.