DeGeneres did her best to encourage people to vote against Proposition 8, the state constitutional referendum that bans gay marriage in the state.
The popular talk-show host and her longtime girlfriend, actress Portia De Rossi, wed earlier this year.
"Watching the returns on election night was an amazing experience. Barack Obama is our new president. Change is here. I, like millions of Americans, felt like we had taken a giant step towards equality. We were watching history," DeGeneres said in a statement issued to E! News Wednesday.
"This morning, when it was clear that Proposition 8 had passed in California, I can't explain the feeling I had. I was saddened beyond belief. Here we just had a giant step towards equality and then on the very next day, we took a giant step away. I believe one day a 'ban on gay marriage' will sound totally ridiculous. In the meantime, I will continue to speak out for equality for all of us."