Around 30,000 people have marched in the Philippines capital Manila, calling on President Gloria Arroyo to quit.
The rally has been seen as a key test of public anger with Mrs Arroyo
It was the biggest demonstration against Mrs Arroyo since she started facing calls to resign over allegations of vote-rigging in 2004 elections.
The size of the protest was an important gauge of public opinion, but it failed to attract the numbers the organisers had hoped for.
One left-wing politician called it "a preview for a bigger storm".
"The situation is not yet ripe for a full-blown 'people power'", said Wilson Fortaleza, of the Sanlakas party, referring to the much bigger protests movements which ousted two of Mrs Arroyo's predecessors.
During the rally, farmers, students, leftist groups and supporters of the former President Joseph Estrada waved placards, balloons and umbrellas that read "Gloria, corrupt, resign now."
Accused of using position to influence 2004 poll
Husband accused of influence-peddling and taking bribes
Son and brother-in-law also implicated
Family denies all allegations
Loudspeakers blared excerpts of wiretapped telephone conversations which sparked the vote-rigging allegations, which Mrs Arroyo has denied.
Protest organisers had said they wanted 50,000 people to take part in Wednesday's event - still short of the hundreds of thousands of people who succeeded in ousting former leaders Marcos and Estrada.
Religious leaders and army leaders backed those revolts, but this time, Catholic bishops have called for a truth commission to investigate the allegations against Mrs Arroyo, but have stopped short of calling for her to resign.
The military has declared it will stay neutral. But some business leaders, civic groups and even a staunch ally, former President Corazon Aquino, have all called on Ms Arroyo to step down.
An aide to Mrs Arroyo said she would defy protesters' calls for her to resign.
"She is standing resolute amid calls for her resignation. She will not stand down... even if today's rally sees half a million people taking to the streets," Michael Defensor, Secretary for the Environment and Natural Resources, told reporters.
Ms Arroyo's problems stem from a taped phone conversation between a woman sounding like her and an election official, in which the woman asks about a lead of "1M".
Critics say it is Mrs Arroyo on the tape, and that she was talking about one million votes, the size of her eventual victory in the election.
Mrs Arroyo has apologised for a "lapse of judgement" in phoning an election official during the 2004 poll, but has denied trying to rig the vote.
In addition to the election controversy, the president also faces separate allegations that members of her family took pay-offs from illegal gambling syndicates.
To try and defuse that controversy, her husband Jose Miguel Arroyo has left the country indefinitely, and is now in the US.
Mrs Arroyo is also losing popularity due to the poorly performing Philippine economy, and proposed budget reforms.