With nearly 79 percent of the votes counted, Aquino surpassed his nearest challenger, former president Joseph Estrada, by more than 4.5 million votes out of the 30 million counted, according to figures from the national Commission on Elections. Two other candidates -- Sen. Manny Villar Jr. and Gilberto Teodoro -- ran far behind.

Aquino said on May 11 that politicians must be responsible to those who elected them.

Nine candidates were running for the presidency.

Aquino, nicknamed "Noynoy," is the son of the former president and Sen. Benigno "Ninoy" Aquino Jr., who was assassinated in 1983 as he returned from exile to lead opposition to Cold War-era Philippine strongman Ferdinand Marcos.

Corazon Aquino, who died in August, took over the leadership of her husband's movement and became the country's first female president in 1986.

The Philippines appeared to pull off a successful inaugural election using automated electronic voting machines with some glitches involving a malfunctioning machine here and there and long queues. Voting was extended by one hour to ensure that people could vote.