Seven Nigerian surgeons, doctors and other medical staff worked together to separate conjoined twins in Bauchi.
The baby girl was conjoined with an unresponsive twin. Officials in the state said the baby who survived is responding well to treatment.
The conjoined twins were born in December last year to a 20-year-old mother in Bauchi state.
Reports say one of the twins was born not breathing, necessitating urgent medical help to separate them.
The surgery was sponsored by the Speaker of the Nigerian House of Representatives Yakubu Dogara.