BACKGROUND: Episodes of patient deterioration on hospital units are expected to increasingly contribute to morbidity and healthcare costs. OBJECTIVE: To determine if real-time alerts sent to the rapid response team (RRT) improved patient care. DESIGN: Randomized, controlled trial. SETTING: Eight medicine units (Barnes-Jewish Hospital). PATIENTS: Five hundred seventy-one patients. INTERVENTION: Real-time alerts generated by a validated deterioration algorithm were sent real-time to the RRT (intervention) or hidden (control). MEASUREMENTS: Intensive care unit (ICU) transfer, hospital mortality, hospital duration. RESULTS: ICU transfer (17.8% vs 18.2%; odds ratio: 0.972; 95% confidence interval [CI]: 0.635-1.490) and hospital mortality (7.3% vs 7.7%; odds ratio: 0.947; 95% CI: 0.509-1.764) were similar for the intervention and control groups. The number of patients requiring transfer to a nursing home or long-term acute care hospital was similar for patients in the intervention and control groups (26.9% vs 26.3%; odds ratio: 1.032; 95% CI: 0.712-1.495). Hospital duration (8.4±9.5 days vs 9.4±11.1 days; P = 0.038) was statistically shorter for the intervention group. The number of RRT calls initiated by the primary care team was similar for the intervention and control groups (19.9% vs 16.5%; odds ratio: 1.260; 95% CI: 0.823-1.931). CONCLUSIONS: Real-time alerts sent to the RRT did not reduce ICU transfers, hospital mortality, or the need for subsequent long term care. However, hospital length of stay was modestly reduced. Journal of Hospital Medicine 2014;9:424-429.