Caylee Anthony, 2, has been missing since June in a case that has received national attention.
The announcement marks the end of a six-month search for the 2-year-old.
"It is with regret that I'm here to inform you that the skeletal remains found on December 1 are those of the missing toddler," Orange County Medical Examiner Dr. Jan Garavaglia said.
She said the cause of death was homicide, but she could not determine how Caylee was killed.
Casey Anthony, 22, faces charges including first-degree murder in the June disappearance of her daughter. Remains described as being those of a small child were found last week a half-mile from Casey Anthony's parents' home, in the area where a meter reader first directed police.
I know the mother was arrested but has yet to be convicted. The evidence hasn't been brought out yet, and everyone is presumed innocent, until proven otherwise. But when they do convict someone, I hope they have a very slow, very painful death. Whether it be by the government or other means. I don't believe in vigilante justice often, but when a child is involved, All Bets Are OFF.