The two sides finished the season third and fourth in the table, with QPR - who are aiming to get back to the top flight at the first attempt - five points behind Steve McClaren's side.
"It's a massive game: obviously we want to get back in the Premier League and there's an awful lot at stake," said Redknapp.
"It's an important game but it's a game of football and we want to make sure we win that game.
"Both teams have got pros and cons but I think they're the favourites and the bookmakers make them the favourites.
"They've been in good form and Steve McClaren has done a fantastic job with them, they're a young side and full of energy."
With the likes of ex-West Ham trio Bobby Zamora, Robert Green and Gary O'Neil in his squad, Redknapp can call on several players who have triumphed in the unique pressure of a Championship play-off final game before.
"Derby are a good team but we're a good team as well, a team full of experience so it's got the ingredients of being a really good match," he said.
"I'm sure they'll have bits to say in the dressing room before the game, like they normally do. Bobby's a good talker, Rob and Gary are experienced too and we've got a lot of players with good experience.
"You can't get too carried away with the occasion you've got to go out and play your football, that's the most important thing. We've got to make sure we've got clear heads, we're focused and we play the way we want to play.
"We played them twice this year and both games were quite even. There wasn't a lot between the two teams, and I'm sure Saturday will be the same."
QPR defender Danny Simpson said the spine of experience running through the team would be a major advantage for his side.
"On the day it will come down to who holds their nerve and who wants it the most," said the former Manchester United and Newcastle player.
"I think we've got a lot of experience and players who have been in that position before and they'll give advice to the players who haven't.
"I made my debut for Man Utd and played in the Champions League for them and I've won the Championship before but this would be the biggest game I've played in.
"If we get through it, it will be up there with my biggest achievements. I'm thinking about it every day and hopefully we'll do it."
Watch QPR take on Derby live from Wembley as part of Sky Sports' 'Ultimate Weekend' from 3pm this Saturday on Sky Sports 1