Apple Inc CEO Steve Jobs waves at the conclusion of the launch of the iPad 2 on stage during an Apple event in San Francisco, California in this March 2, 2011 file photo. Jobs has resigned his position as CEO of Apple, the company announced August 24, 2011.[Photo/Agencies]

Apple Chief Executive Officer Steve Jobs (L) stands beneath a photograph of him and Apple-co founder Steve Wozniak from the early days of Apple during the launch of Apple's new "iPad" tablet computing device in San Francisco, California, in this January 27, 2010 file photograph.[Photo/Agencies]

SAN FRANCISCO-- Steve Jobs has resigned as the chief executive officer (CEO) of Apple, the company said on Wednesday.

In a press release, Apple said that its board has named Tim Cook, previously Apple's chief operating officer (COO), as the company's new CEO.

According to Apple, Jobs has been elected chairman of the board and Cook will join the board, effective immediately.

"I have always said if there ever came a day when I could no longer meet my duties and expectations as Apple's CEO, I would be the first to let you know. Unfortunately, that day has come," Jobs said in a letter released by Apple.

"As far as my successor goes, I strongly recommend that we execute our succession plan and name Tim Cook as CEO of Apple," he added.

"I believe Apple's brightest and most innovative days are ahead of it. And I look forward to watching and contributing to its success in a new role," said Jobs.

Jobs, 56, disclosed in August 2004 that he had been treated for a rare form of pancreatic cancer, saying the tumor was diagnosed in time and he had undergone surgery to remove it.

In the following years, the thin, almost gaunt appearance of Jobs constantly inspired speculations about his health.

In early Jan. 2009, Jobs said that his apparent weight loss is caused by a treatable hormone imbalance. But about a week later, he admitted that the issue was more complex than he had thought and then took a medical leave for nearly six months.

In June 2009, Methodist University Hospital Transplant Institute in the US state of Tennessee confirmed that Jobs received a liver transplant at the institute.

In January this year, Jobs announced that he is taking another medical leave, without disclosing in detail about his health conditions.

The Apple co-founder is a legendary figure in Silicon Valley and is widely seen as the symbol of Apple.

In Aug., Apple temporarily surpassed Exxon Mobil to become the world's most valuable company.

"Steve's extraordinary vision and leadership saved Apple and guided it to its position as the world's most innovative and valuable technology company," Art Levinson, chairman of Genentech and a member of Apple's board, said Wednesday in a statement.

"Steve has made countless contributions to Apple's success, and he has attracted and inspired Apple's immensely creative employees and world class executive team. In his new role as Chairman of the Board, Steve will continue to serve Apple with his unique insights, creativity and inspiration," Levinson noted.