The woman, who is in a critical condition did the act allegedly in an inebriated condition, the police said.
The incident occured in Rekulachoudapur of Nawabpet mandal, March 31 at around 4 pm, when the woman took her three children including two boys and a girl near a well and threw them in, an investigating officer told PTI.
The deceased were identified as K Agni (6), K Shilpa (7) and K Charan (2), he said.
Some villagers immediately jumped into the well and tried to save the children, but the three kids died while their mother was rescued, he said.
However, her condition remains critical and she has been rushed to a hospital.
"The woman is an alcohol addict. It seems that she was in a mentally-disturbed state. Her husband is a driver and there were no family problems. She was in an inebriated condition when the incident happened," the police officer said based on a preliminary investigation.
Nawabpet police were in the process of booking a case, while the bodies of the three children have been sent for post-mortem.
Further investigations are on.