In the past 8 years since September 11, many improvements have been made to the National response capabilities; however, the "all hazards" approach is still inadequate to respond to a moderate pandemic outbreak. Shortcomings of our fragile healthcare framework combined with the prolonged duration of a pandemic make it difficult to prepare for such a catastrophic disaster. Therefore, the purpose of this study was to investigate the factors ensuring hospital viability during a pandemic influenza outbreak. To accomplish this, the study employed a comparative case study methodology utilizing four prominent emergency management events: 1918, Spanish flu (H1N1); 2003, SARS outbreak; 2005, Hurricane Katrina, and the 2009, Swine flu (H1N1) outbreak, for the purpose of finding common measures enabling a hospital to mitigate, prepare, respond, and recover from a pandemic. After reviewing the case study literature, 117 viability measures were identified. Furthermore, the concepts from the literature review coupled with the case study results led to discovery of seven hospital viability measures that will assist in mitigating a moderate pandemic, which are: maintaining a hospital's critical axis, staffing, security, logistics, surge capacity, public affairs, and emergency operations planning. Focusing preparedness efforts in these areas will provide protection from the next pandemic.