The Foxes go to Selhurst Park five points clear at the top of the Barclays Premier League.
They are favourites to take the title and face a Palace side without a win in their last 12 league games with their last victory coming at Stoke in December
The hosts have reached the FA Cup semi-final, where they face Watford, but Alan Pardew's side have dropped to 15th in the Premier League
But, with Leicester expected to win in London, Ranieri is cautious against their out-of-form hosts.
He said: "Yes, it's very strange. When we played here it was a very difficult match, I was so happy the last time because we made the first clean sheet if you remember. Also at the end of the match I didn't say hello to Alan Pardew - I made a mistake.
"I was so happy I went to the pitch because I recognised it was a very, very difficult match to beat them. It will be the same on Saturday, it will be a very, very tough match."
Source: PA