Adviser to the Prime Minister on Finance and Revenue Shaukat Tarin was sworn in as senator on Friday.
Senate Chairman Sadiq Sanjrani administered the oath to the newly-elected senator.
Earlier, Shaukat Tarin was elected senator from Khyber Pakhtunkhwa (KP).
The seat fell vacant after Pakistan Tehreek-e-Insaf (PTI) leader Muhammad Ayub Afridi resigned as member of the upper house last month.
Out of 145 members of the provincial assembly, 122 cast their votes during Senate by-elections. The finance adviser won the seat after securing 87 votes.
