The 45-year-old suffered criticism after failing to award a number of penalty claims from the Blues at Stamford Bridge three years ago, which sparked outrage from the likes of Didier Drogba and Michael Ballack.
The final blow was issued to the former Premier League champions when Andres Iniesta scored in the closing minutes to knock Chelsea out of the competition.
"I still get a few death threats, but they go straight into the garbage box," Ovrebo told The Times.
"I don't take them seriously, although sometimes I wonder about the people who send them. Just yesterday I got an e-mail from a Chelsea fan saying he wanted to kill me and my family.
"Everyone who knows the laws of the game knows I should have done things differently, but that's the life of a referee. In a strange way, I was actually satisfied with the way we all managed to keep calm in a tense situation."
Chelsea welcome Barcelona to their home ground this evening for the first leg of the highly-anticipated semi-final of the elite competition.