The fire broke out around 6:00 a.m. Monday on the 100 block of Clinton Street in Delaware City, New Castle County.
Firefighters arrived to find heavy fire coming from the second floor of the house.
Teyona Watts, 19, and her two daughters - 3-year-old Brianna and 9-month-old Jordan - were found in the second floor.
CPR was given to the victims and they were then rushed to Christiana Hospital.
Watts was pronounced dead at the hospital.
The girls were admitted in critical condition but later died.
The anguished young father, Travis Jones, had to be restrained by friends after returning home to learn that his family was gone. He had left for work just an hour before the fire began.
Travis told Action News that he went to the hospital and held baby Jordan in his arms as she fought for her life, but ultimately succumbed to her injuries.
"She fought. She fought hard. I was at the hospital, I was holding her and she just faded away," Travis said. "Right in my hands."
Travis said Brianna was destined to be a superstar.
"She was a little star, man. She made everybody's life a little bit brighter," said Travis.
Through tears he continued: "I miss her so much. I want my whole family back."
The grandfather of the children, Robert Simpers, said the girls occupied a tender spot in his heart.
"Brianna was really starting to dig her pop-pop. I was her world. And little Jordan, every time she saw me she had a smile for me," he said.
Teyona's childhood friends gathered outside the house remembering a happy young woman who lit up the room.
"She would definitely make you smile. Her laugh was unforgettable," said Nicole Cebenka.
"She was one of a kind," said Ashley O'Donnell. "She always made everybody feel good."
Friends say Teyona and Travis were childhood sweethearts and were engaged to be married. Their landlord, Pauline Murray, says they were a caring young couple.
"I am absolutely stunned," Murray said.
Fire investigators believe the flames erupted in the rear of the house in the kitchen area.
They say it appears to be accidental at this point, but they're not ruling out the possibility of foul play. It could be days before the cause is known.