Newark Fire Department spokesman Capt. John Brown says seven others with non-life threatening injuries were taken to University hospital. The 5-year-old was flown by helicopter to the St. Barnabas Medical Center.
The children were on the second-floor of of a three-story home in the city's North Ward. The fire broke out just after midnight.
Landlord Noeme Gaton tells The Star-Ledger of Newark that nine people lived in building. She says the family of five who lived on the second-floor had just moved in over the summer.
Brown says the cause of the fire is under investigation.