Abstract Purpose The reported actual compliance for severe sepsis bundles was very low, suggesting the presence of barriers to their implementation. The purpose of this study was to assess the influence of full-time intensivist and nurse-to-patient ratio in Korean intensive care units (ICUs) on the implementation of the severe sepsis bundles and clinical outcome. Materials and Methods A total of 251 patients with severe sepsis were enrolled from 28 adult ICUs during the July, 2009. We recorded the organizational characteristics of ICUs, patients' characteristics and clinical outcomes, and the compliance for severe sepsis bundles. Results Complete compliance with the resuscitation bundle and totally complete compliance with all element targets for resuscitation and management bundles were significantly higher in the ICU with full-time intensivist and a nurse-to-patient ratio of 1:2 ( P < .05). The hazard ratio (HR) for hospital mortality was independently reduced by the presence of full-time intensivist (HR, 0.456; 95% confidence interval, 0.223-0.932), and a nurse-to-patient ratio of 1:2 was independently associated with a lower 28-day mortality (HR, 0.459; 95% confidence interval, 0.211-0.998). Conclusions The full-time intensivist and the nurse-to-patient ratio had a substantial influence on the implementation of severe sepsis bundles and the mortalities of patients with severe sepsis.