The Toffees midfielder enjoyed a profitable loan spell with the Rams between January and May 2004, when he scored three goals in 17 appearances.
"I thoroughly enjoyed my time at Derby," said the 26-year-old. "It was a loan spell which I needed at the time and I've got fond memories of my time playing there.
"Derby were in the Championship relegation zone when I joined them and when I was there we managed to get ourselves out of trouble, so that was pleasing. When I came back to Everton I got my chance.
"I did a few things right when I was at Derby which was good for myself and good for them."
Not that he has much sympathy for the Rams' current plight.
Billy Davies' men are in the thick of the Barclays Premier League relegation zone after a woeful start to the season.
Osman added: "It's an important game in the Premier League, as they all are, and it's one we're looking to win.
"Derby are a newly-promoted side and every game to them is going to be a cup final, so we've got to make sure that we match them.
"It's always tough when you first come into the league, but they'll be battling as hard as they possibly can.
"With a bit of luck they could have had a few more wins."