David Bowie once described Reed as his all-time hero. Others who credit his influence include The Jesus and Mary Chain, REM and U2.
His passing was announced with a cryptic note on his Twitter and Facebook pages, possibly posted by himself, saying simply: "The Door."
Iggy Pop said Reed's death was "devastating news".
The Who said: "R.I.P. Lou Reed. Walk on the peaceful side."
And author Irvine Welsh tweeted: "I really doubt that there would have been Trainspotting without Lou Reed."
Bisexual Reed, born in Brooklyn, always played down his musical talents