Jeremy Zwinger, president and chief executive officer of the Rice Trader, which organised the competition, said 25 rice samples from 15 countries and regions, including Cambodia, Thailand, Vietnam, India, Myanmar and the US joined the contest.
"Rice from Cambodia and Thailand is awarded the best rice for this year," he announced during the World Rice Conference, and added that the judgement was made mainly based on the rice's appearance and taste.
Sok Puthyvuth, president of the Cambodia Rice Federation, said it was the third year that Cambodia's fragrant rice won the award.
"It is another significant milestone for Cambodia's rice industry," Xinhua quoted him as telling reporters. "The award clearly reflects our rice's high quality and I hope that the reputation of our rice will grow internationally."
He said Cambodia's Romduol rice species won the prize.
According to Puthyvuth, during the first 10 months of this year, Cambodia exported 304,788 tonnes of milled rice, earning about $180 million.
Chookiat Ophaswongse, honorary president of the Thai Rice Exporters Association, said Thailand's brown jasmine rice also won the prize.
"We are one of the world's largest rice exporters and our rice's quality is internationally recognised," he said, adding that so far this year, Thailand has exported about eight million tonnes of milled rice and is expected to reach 10.5 million tonnes by the end of the year 2014.