The United veteran has clocked up 548 appearances for United, scoring 138 goals.
Ferguson added: "Scholes' great asset down the years has been appearing in the box late. The number of goals he has scored for us from midfield is unique.
"His other big assets are his passing, his composure and his thinking during a game.
"At 33, I regard him just as highly as I did when he was 23. Players like him and Ryan Giggs, who look after themselves, give themselves extra years.
"Look at Giggs. He's flying this season. Giggs came on at Reading and the stats show he made 45 sprints in the second half. That's incredible for a player of his age."
Giggs, at 34, remains a key figure in United's squad, after picking up a record nine titles for the club.
Ferguson cannot envisage Old Trafford without the pair. He declared: "What I've come to realise with these two players is I can no longer see an end to their careers. In fact, I don't expect to see an end!
"There must come a day when it will end. But the way it's looking now, I can't see that end coming. I think I'll be away from the club before they will.
"Bearing in mind their longevity, they must be the best two players I've had.
"Giggs has been here since the age of 13 and Scholes is the same. They have both been here as long as I have."