Bruce Springsteen and the Rolling Stones lead the mega-stars performing for an estimated global audience of two billion.
Among the performers - many of whom have property or other close links to New York - were the Rolling Stones, Eric Clapton, Alicia Keys, Bon Jovi, Chris Martin, The Who and Kanye West.
More than 130 people were killed when Sandy struck the East Coast of the US in October.
Thousands more were left homeless as the storm tore through areas of New York, New Jersey and Connecticut, causing billions of dollars' worth of damage.
