It happened around 6 a.m. on the 1800 block of Cantwell Court. Raleigh Fire Department said crews responded to a cardiac arrest call.
They found a fire that erupted in the kitchen and quickly extinguished.
A 1-year-old girl and a 4-year-old boy were taken to a hospital for smoke inhalation. They both died from their injuries.
The mother of the children was also inside the apartment at the time of the fire. She was not injured.
The Raleigh Fire Department said the fire was traced to a cooking incident. Raleigh Police said the incident is still under investigation.