The Election Commission of Pakistan (ECP) on Friday ordered re-polling in PK-23, Shangla I constituency.
"The polls and their results in PK-23 have been declared void over low turnout of female voters," the ECP said.
Women votes were less than 10 per cent of the total polled votes in the constituency, it added.
Pakistan Tehreek-e-Insaf (PTI) candidate Shaukat Yousafzai had emerged victor from PK-23 during the July 25 polls.
Earlier, the ECP had withheld Yousafzai's victory notification.
According to records, 86,698 women were registered to vote from the constituency. However, only 3,505 women cast their votes in violation of ECP regulations.
Ahead of the elections, the ECP had said that results of any constituency would be declared invalid should the female turnout be lower than 10 per cent.