On June 20, 2007, the Commission on Elections officially proclaimed the ratification of Republic Act 9408 converting the Municipality of Mati into a component city.
There were 18,267 actual voters out of the 51,287 registered voters in 26 villages and 266 polling precincts during the June 18 plebiscite. Final tabulation showed Yes – 18,267 votes (35.6%); No – 846 (1.6%).
The cityhood of Mati and 15 others were however questioned by the League of Cities of the Philippines before the Supreme Court.
League of Cities of the Philippines v. COMELEC is a landmark decision of the Supreme Court of the Philippines about the validity of the cityhood laws of sixteen municipalities in the Philippines. The case clarifies the requirements for the conversion of a Municipality into a Component City. The Court in its final decision ruled that the cityhood laws of the sixteen municipalities in the Philippines are constitutional.