Major cities, including Sydney, Shanghai, Dubai and Berlin have marked the start of 2013 with large fireworks displays.
Among the most spectacular celebrations were ones in Sydney, which centred on the harbour bridge, and Dubai, where the world's tallest building, the Burj Khalifa, formed the centrepiece.
Some 1.5 million people are estimated to have turned out to watch the event in the Australian city with more than 100,000 firework patterns, costing £4.2m.
One of the country's most famous singers, Kylie Minogue, was creative ambassador and she picked the colours and the music.
The pop star pressed the button that set off seven tons of fireworks.
Shanghai ushers in the New YearThe Dubai show had three elements - light, water and fire - and projections on a 210-metre long screen.
Moscow had the Kremlin as its backdrop, while Jakarta marked 2013 with a massive four-mile street party.
Sixteen large stages were built along the normally busy, eight-lane motorway which runs through the heart of the Indonesian capital.
There was a fireworks display at the Kremlin in MoscowCouples kissed in New York's Times Square as ticker tape and fireworks welcomed in 2013 in style.
Thousands packed the iconic square in Manhattan as singers belted out the Frank Sinatra classic New York, New York.
The countdown was the first in decades without television host Dick Clark, who died in April.
North Korea put on a pyrotechnic display in PyongyangThere were also celebrations on a grand scale in Hong Kong and Shanghai.
This year's fireworks display, which cost about £1m, was said to be the biggest ever in the southern Chinese city.
Meanwhile, North Korea welcomed 2013 with reportedly the first ever New Year's fireworks display the country has held as Tokyo reverberated to the sound of the city's Watch-Night Bell.
The bells were struck 108 times at temples all over Japan to symbolise the beginning of a prosperous New Year.
Auckland began the countdown to 2013Burma rang in the New Year with its first public countdown and a fireworks display, a celebration unprecedented in the former military-ruled country.
Around 90,000 people gathered at the countdown venue - a large field in Rangoon - for a chance to do what much of the world does every year at this time.
"This is very exciting and also our first experience in celebrating the New Year at a big countdown gathering. We feel like we are in a different world," said Yu Thawda, a university student who joined the party.
The atmosphere of celebration was muted in some places.
British troops at Camp Bastion in Afghanistan see in the New YearMany European nations planned scaled-back festivities and street parties for 2013 which is projected to be a sixth straight year of recession amid Greece's worst economic crisis.
Hotels, clubs and other venues in New Delhi cancelled festivities after the death of a gang rape victim which has led to days of protests and mourning.
The first major city to see in 2013 was Auckland, New Zealand, which had a spectacular fireworks display.
Crowds packed the city centre to watch the annual event at the city's Sky Tower, which stands more than 1,000ft tall.
The central Pacific Ocean island of Kiritimati (Christmas Island) and the eastern-most island in the island nation of Kiribati were the first to usher in the new year at 1000 GMT.
American Samoa, an unincorporated territory of the US in the southern Pacific Ocean, was the last place on Earth to herald in the new year on Tuesday at 1100 GMT.