In May 1998, Cayetano was elected senator, garnering the second highest number of votes. The freshman senator became the Chairman of the Committee on Justice and Human Rights and Vice-Chairman of the Committee on Public Order and Illegal Drugs. He is also the Minority Leader of the Commission on Appointments and was a member of the Judicial Bar Council and BIR Oversight Committee. Before the 11th Congress adjourned February 9, he became the Senate Minority Leader Floor Leader, making him an ex-officio member of all Senate committees.