The couple, who already have a two-year-old son, Mason, have named the new born daughter Penelope Scotland, reported E! Online.
Penelope was born at The Cedars-Sinai Medical Center and weighed seven pounds and 14 ounces.
"Scott and I are overjoyed to welcome our precious angel Penelope Scotland Disick into our lives. We are forever blessed. Mommy and baby are resting comfortably," said Kourtney, 33.
According to Kourtney's mother Kris Jenner, her daughter has had a natural birth.
"It was great. She had an easy delivery. Penelope is so cute. She looks just like Mason. She's so beautiful. We are so happy," she said.
Two years ago, when Mason was born, Kourtney and Scott showed his birth on the family's TV show, 'Keeping Up With The Kardashians'.
But during an appearance on the Tonight Show a couple of weeks ago, Kourtney said they hadn't decided whether they would show Penelope's.
"We're gonna film it again ourselves, and honestly, my experience last time was so peaceful and calm and everything you don't see in the movies," she said.
Back in May, Kourtney's sisters Kim and Khloe and all the family including Kim's rapper beau Kanye West, threw a baby shower for her.
