Nosocomial transmission of severe acute respiratory syndrome from critically ill patients to healthcare workers has been a prominent and worrisome feature of existing outbreaks. We have observed a greater risk of developing severe acute respiratory syndrome for physicians and nurses performing endotracheal intubation (relative risk [RR], 13.29; 95% confidence interval [CI], 2.99 to 59.04; p = 0.003). Nurses caring for patients receiving noninvasive positive-pressure ventilation may be at an increased risk (RR, 2.33; 95% CI, 0.25 to 21.76; p = 0.5), whereas nurses caring for patients receiving high-frequency oscillatory ventilation do not appear at an increased risk (RR, 0.74; 95% CI, 0.11 to 4.92; p = 0.6) compared with their respective reference cohorts. Specific infection control recommendations concerning the care of critically ill patients may help limit further nosocomial transmission.