The Equality Act 2006 made it illegal for Catholic adoption agencies to refuse to place children with gay couples.
Bishop Kieran Conry explained that it was not worth the Church fighting a legal battle it was going to lose.
The adoption agency connected to his diocese changed its name to the Cabrini Children's Society and agreed to comply with the law.
"It's not that Catholics aren't interested in this any more," said Bishop Conry. "But we're not going to have a public fight that we're possibly going to lose and come out of it with everyone suffering."