Samsung has sold 100 million of its flagship Galaxy S smartphones two years and seven months since the first model in the series was released.

It sold 25 million Galaxy Ss since 2010, 40 million Galaxy S2s since 2011, and 41 million Galaxy S3s since last year.

Staffers pose to mark the sale of 100 million Galaxy S series phones in Suwon on Monday. /Courtesy of Samsung Electronics

The series is the second smartphone brand after Apple's iPhone series to achieve the milestone.

Samsung fell behind Apple in 2009 as the iPhone took the market by storm but managed to turn the tide with the Galaxy S in May 2010. The Korean giant accounted for 34 percent of the global smartphone market in the third quarter of last year, while Apple took up 16 percent.

The success of the Galaxy S series is due to innovative functions and leading technologies Samsung has in areas like semiconductors and displays, the company said.

The firm plans to launch another model in the series this spring.