Hong Kong has been declared free of Sars, 20 days after the last confirmed case of the disease in the territory.
China has seen thousands recover from the disease
The World Health Organization called the development a "very significant achievement in the history of Sars control", following 296 deaths from the disease in Hong Kong.
"The whole world can now feel safer from the Sars threat," said David Heymann, the WHO's executive director of communicable diseases.
But officials are warning that the territory must remain vigilant if it is to avoid the kind of recurrence of the pneumonia-type disease experienced by the Canadian city of Toronto.
Known death tolls:
Mainland China: 348
Hong Kong: 298
Source: WHO/local authorities
Toronto reported two new Sars deaths on Sunday, despite the apparent tailing off of the disease there.
The BBC's Francis Markus says that, even with Hong Kong celebrating the all-clear, the impact of Sars on the territory is likely to linger.
Hong Kong's economy was already in a battered state before the disease struck, and the virus has also had political implications.
The Hong Kong authorities' response to the outbreak has been the subject of widespread criticism, and the spread of the disease - which originated in southern China - has underlined Hong Kong's vulnerability to events within China.
Only Beijing, Taiwan and Toronto are still on the WHO list of Sars-infected areas following the disease's peak in March and April.
The UN body attributes the success in tackling the disease to effective quarantine methods.
Sars has killed more than 800 people worldwide - most of them in Asia - since the disease first appeared in southern China last November.
Hong Kong had one of the hardest outbreaks to control
In Hong Kong, 296 people died of the disease and 1,755 became ill.
At the height of the Sars epidemic in early April, Hong Kong had 60 to 80 new cases of the disease each day.
Hundreds of thousands of residents wore surgical masks, and stayed away from public places in an attempt to avoid catching the virus
There are still 28 people in hospital - including 11 in intensive care - but 1410 people have recovered and been discharged.
Mr Heymann said controlling Sars in Hong Kong had been especially difficult.
"Hong Kong, with its dense population and fluid border with China, had one of the hardest outbreaks to control.
Hong Kong chief executive Tung Chee-Hwa, gave a news conference at a housing estate on the Kowloon peninsula, which saw the worst outbreak in the city.
We really need to push
forward and learn from this experience.
Hong Kong chief executive
More than 300 residents were infected by faulty sewage pipes, which left at least 42 people dead.
"This could come again," he said. "We really need to push forward and learn from this experience."
The latest Sars victims in Toronto were a 55-year-old man and an 81-year-old woman, the Canadian Government said.
Thirty-eight people have now died of Sars in Canada - the only country outside Asia to have reported Sars fatalities.
As Hong Kong welcomed its removal from the list of locations affected by Sars, it also mourned a second hospital doctor to have been died from Severe Acute Respiratory Syndrome.
Dr Cheng Ha-yan, 30, was buried with honours at Gallant Garden, a special graveyard for those who died performing their duties with courage.
Dr Cheng - the eighth health care worker in Hong Kong to die of Sars - had volunteered to work in a Sars ward.