The Asian football confederation president said he will challenge the 75-year-old Blatter for the FIFA presidency on June 1 in Zurich, setting the stage for a head-to-head battle against the man who has led the organization for 13 years.
"Today after careful study, consultation and consideration, armed with my love and passion for football, believing that our game is about fair competition, I have decided to contest," said bin Hammam, who would be the first Asian to hold the post if elected.
"My chances, I would say, are 50-50." Blatter, one of the most powerful men in world sport, has not faced a serious challenge to his post since 2002.
The 61-year-old bin Hammam, who ended months of speculation about his intentions during a news conference at AFC headquarters, is seen as a serious contender -especially after playing a pivotal role in brining the 2022 World Cup to his native Qatar.
"Sepp Blatter is a very experienced person and has made a significant contribution to the development of the game worldwide when he was a general secretary and when he was elected as president. The world knows him very well," bin Hammam said.
"But I also believe there is always a time limit for everything and now the time is for new faces, new blood, new air, too. This is actually my message and I hope the voters are going to address these things."
In a 17-minute speech, Hammam offered to broaden FIFA's decision-making power and spread its wealth. He proposed creating a new FIFA board to replace the existing executive committee, which some regard as concentrating power in too few hands.
Bin Hammam said the FIFA president should be chairman of a 41-member board, instead of 24, putting forward a plan that would dilute the power of Europe and South America - football's traditional powers - while boosting the representation from elsewhere.
Under the plan, Europe would have 12 members, up from eight, and South America would go from three to four. The other bodies would double their representation: the African and Asian federations from four to eight each, North America from three to six and Oceania from one to two.
Bin Hammam described FIFA as being too bureaucratic and centralized, questioning its efficiency in technical and legal areas. He hopes to set up a new transparency committee, ensure fair distribution of World Cup revenues and double the annual grants to FIFA's 208 members to $500,000.
The upper limit for development projects, which provide valuable cash support for smaller nations, should be doubled to $1 million, he said.
The Qatari has long held ambitions to lead FIFA, which has had only eight presidents in its 111-year history. All were European except the long-serving Joao Havelange, who is from Brazil and was Blatter's predecessor. Stanley Rous, Havelange and Blatter have been the only presidents in the past 50 years.
Bin Hammam warned Blatter to expect a challenge when he said in February 2010 it was time for FIFA to have Asian leadership.
A month later, he was rebuffed by his FIFA executive colleagues in a motion to limit the terms of future presidents. The motion was interpreted as testing Blatter's strength. Bin Hammam told The Associated Press that, despite the setback, the "situation can be different" in 2011.
They made peace when Blatter visited the Gulf last April and said the region was ready to host a World Cup. However, Blatter is believed to have backed the United States for the 2022 tournament.
Blatter has not been challenged since 2002, when he defeated African confederation president Issa Hayatou 139 votes to 56.
Bin Hammam must now find a majority of FIFA members sufficiently unhappy with Blatter's reign or tempted by new leadership. He needs the formality of being nominated by one of FIFA's 208 national federations. Blatter has been nominated by Somalia.
Bin Hammam, however, is far from universally popular even within the Asian confederation, having only won re-election to the FIFA executive committee last year by two votes after a fiercely contested challenge from Sheik Salman bin Ebrahim Al-Khalifa of Bahrain.
"I hope that Asia is going to be united behind me, but also the other confederations where I enjoy a lot of friendship and relationships. I hope also those people are going to support me," he said.
A businessman who made his fortune in construction, bin Hammam's rise in the football world began in administration rather than as a player, becoming president of Qatari club Al Rayyan at age 24. His acumen as an administrator saw him soon take over the helm of Qatar's volleyball and table tennis bodies.
He took command of the Qatar Football Association in 1992, and four years later was elected by the AFC to the FIFA executive committee.