A report from the Trust for America's Health, says the United States only has 965,256 staffed hospital beds, and in the event of a pandemic, half a million Americans could die and more than 2 million could end up in the hospital with serious complications.
This would happen if an even moderately severe strain of a pandemic flu occurs.
The state-by-state analysis, by the non-profit group, adds to growing demands that the United States needs to be better prepared for a large outbreak of disease, whether natural or brought on by war or terrorism.
The Trust's executive director, Shelley Hearne, said in a statement, that this is not a drill or a planning exercise.
Each year, influenza kills an estimated 36,000 Americans and puts 200,000 into hospital.
Every few years a more serious strain strikes and on average a so-called pandemic strain emerges once every 27 years.
The more virulent strains sweep around the world within months.
The world was hit by pandemics in 1918, killing up to 40 million people globally, and in 1957 and 1968.
Many health experts say the world is overdue for another and they fear the avian flu in Asia may be it.
The World Health Organization says an H5N1 avian flu pandemic could kill up to 7.4 million people globally, because people lack immunity to it.
As yet Avian flu has not acquired the ability to pass easily from person to person, but experts say it would spread rapidly if it does.
But according to the report another strain of flu with pandemic characteristics could also wreak havoc.