The Suwannee County Sheriff's Office says the children, ages 1, 4, and 6, couldn't be revived when they were found Sunday at a home in Live Oak in north Florida.
Officials say the children lived at the house with the grandmother of two of the children and the other child's mother. The women were roommates.
The sheriff's office says in a Facebook post that one of the women went inside to use the restroom and couldn't find the children upon returning.
The women searched the property and found the children in the freezer.
The sheriff's office says foul play isn't suspected. The case will be forwarded to prosecutors for review.