The pitbulls were pulled from a home in the area of Pinedale and Blackstone Tuesday morning.
Fresno fire says the fire was caused by a malfunctioning warming lamp being used to keep the puppies warm at night.
Small animals are very susceptible to suffocation from smoke inhalation.
The fire department says the crew's quick actions prevented this from happening.
All 12 puppies appeared to be healthy.
As the temperatures get cooler at night, firefighters want to remind everyone to be sure heating appliances are properly maintained and heating appliances are clear of any combustible material.