Roco was elected to the Senate in 1992 and 1995 serving until 2001, making many contributions that led many to recognize him as an “outstanding senator”. He wrote the law which reformed the nation’s banking system; this earned him the title “Father of the Bangko Sentral”. Some other laws that he wrote resulted in the liberalization of the banking industry and the strengthening of the thrift banks. In addition, he wrote the Intellectual Property Code and the Securities Regulation Code.

Roco has also made several contributions to education in the Philippines. He helped fund the teachers’ cooperatives as well as the increment mandated by the Magna Carta for Public School Teachers for retiring public school teachers. On the students’ side, he helped bring computers into Philippine universities, colleges, and public schools. In addition, he devised a plan for meal scholarships for poor students at the Philippine Normal University.

Roco wrote several bills targeted at protecting and prioritizing women in the Philippines. He wrote the Women in Nation Building Law, the Nursing Act, the Anti-Sexual Harassment Law, the Anti-Rape Law, and the Child and Family Courts Act. He also let women play major roles in the Department of Education’s literacy program. Out of thanks to his services for women, many women’s groups named him an “Honorary Woman”.

He also drafted a bill that abolished double taxation on Filipinos working abroad.

He was given the Bantay Katarungan award by Kilosbayan for playing an integral role in the Senate impeachment trial of then-president Joseph Estrada who was impeached by the House of Representatives on 2000 for graft and corruption. bribery, betrayal of public trust and culpable violation of the Philippine Constitution. Unfortunately, the impeachment trial was not concluded and on 2001, Estrada was ousted from power by another People Power uprising.