Malaysians have gone to the polls in a race analysts say is too close to call even through longtime opposition leader Anwar Ibrahim is forecast to win.
Anwar has campaigned on a promise to fight corruption in Southeast Asia's third-largest economy. He is challenging jailed ex-leader Najib Razak's scandal-hit party seeking to cement its power.
There were reports of long lines at polling centers across the country, indicating a strong turnout from among the 21 million registered voters.
A record 945 candidates are contesting for seats in parliament across the largely Muslim nation.
The stakes are high with Malaysians facing soaring food prices, and parts of the country being battered by flash floods sparked by monsoon rains.
Najib's United Malays National Organisation (UMNO) suffered a humiliating defeat in the 2018 general election in the wake a massive corruption scandal at state fund 1MDB after years of dominating Malaysian politics.
The former prime minister, who was at the center of the 1MDB storm linked to Saudi Arabia, is currently serving a 12-year jail term.
Anwar was quoted as saying that he was "cautiously confident" his Pakatan Harapan (Alliance of Hope) could secure a simple majority in the 222-member parliament.
He has loomed large in Malaysia's politics for many years, marked by a long litany of charges which has hampered his dream of leading the country.
"A win today would certainly be gratifying after more than two decades of fighting to win the hearts and minds of the people," the 75-year-old politician said as he cast his vote in Penang state.
Anwar is running against caretaker Prime Minister Ismail Sabri Yaakob, from the ruling coalition. His other rivals are former prime ministers Mahathir Mohamad and Muhyiddin Yassin who head two other coalitions.
Corruption was a key issue during the campaign, with opposition parties repeatedly warning that if UMNO wins, Najib could walk free and graft charges against other party leaders could be dropped.
The 1MDB fund was set up by Najib in 2009 to pay for major new economic and social developments in Malaysia.
The 1MDB scandal, in which billions of dollars in state funds were diverted to Beverly Hills properties, a superyacht, a Hollywood film and Najib's own bank account, sparked investigations in Singapore, Switzerland and the United States.
Saudi Arabia has said funds found in Najib's personal account were a donation.