In an e-mailed statement, the South Korean electronics giant said sales of the S3 hit 20 million 100 days after its debut in May -- three times faster than sales of the Galaxy S2 and six times quicker than those of Galaxy S -- China's official Xinhua news agency reported Thursday.
Sales passed 10 million in 50 days, representing around 200,000 sales per day, Samsung said.
The Galaxy S3 has sold well in all global markets, the company said -- with sales reaching 6 million in Europe, 4.5 million in Asia and 4 million North America.
Sales in South Korea have amounted to 2.5 million, it said.
"The GALAXY S3 has enjoyed tremendous attention and popularity since its launch in May, and we are thrilled with its success," said Shin Jong-kyun, president of Samsung's IT and mobile communications division.
The sales figures were announced while Apple is seeking a ban on the sale of the S3 in the United States after a federal court jury found Samsung guilty last month on infringing on six of seven Apple patents on smartphones and tablets.