Vismitha from Annur near here, was suffering from fever for the last 10 days and was undergoing treatment in a private hospital there.
As a blood test confirmed dengue, the girl's parents shifted her to the Coimbatore Medical College hospital here two days ago, the sources said.
The girl, who was undergoing treatment in the special ward, died late last night.
Meanwhile, 42 dengue patients and 184 persons with different types of fever were undergoing treatment in the hospital, they said.
In another incident, a 12th standard student, Jagadeeshan died of dengue in a private hospital in nearby Salem, in the early hours of today, police said.