The Polish striker, has been linked with a move away from the German giants at the end of the season.
He only has a year left on his current contract and has so far failed to agree an extension.
Barcelona were believed to be leading the chase to sign Lewandowski ,who has scored a staggering 45 goals in just 39 games in all competitions this season.
Both Manchester United and Arsenal have also been linked with a big money move for the star.
And Atletico Madrid are also deciding a swoop for the top striker.
When pressed on whether Bayern would sell now rather than risk losing him for nothing, he insisted that the ace is staying.
Kahn added: “He will stay with us. Robert knows what he has in Bayern.
“We know what we have in him.”