Over 400,000 patients die each year due to "mistakes" in hospitals across the country and a new report card is grading Long Island hospitals on how safe they are for patients.

The "Leapfrog Hospital Safety Guide" gives an "A" to three Long Island hospitals.

Mather Hospital in Port Jefferson, St. Charles Hospital in Port Jefferson and St. Francis Hospital in Roslyn all scored high marks.

Three of Long Island hospitals got "Ds," including Long Island Community Hospital, formerly Brookhaven Memorial in Patchogue, Nassau University Medical Center in East Meadow and Mercy Medical Center in Rockville Centre.