"Been AWOL from Twitter. I totally have a good reason: TINY HUMAN #3 is here and she's perfect! Babies are good. Life is good. #2shows3kids," Rhimes wrote on Twitter.
Further details on the adoption were unavailable.
In 2002, Rhimes adopted her first daughter, Harper, before she had even created her flagship series Grey's. Second daughter Emerson Pearl joined the family in February 2012.