The incident occurred under Nagireddypet police station limits between 9.30 am and 10 am, they said.
J Vinoda took her daughters J Nandini (5) and Soumya (five-month-old) along with her and jumped into the canal, Police Inspector Satish Reddy said, adding their bodies were subsequently fished out.
Vinoda's husband Sailu, an auto-rickshaw driver, used to regularly harass her for delivering two daughters and not son, Reddy said quoting a complaint lodged by Vinoda's brother.
Police have registered a case for abetment of suicide and under various sections of IPC against Sailu, Reddy said, adding police are yet to make any arrest.