Some 57,000 fans of football club Sport have signed up as donors in Pernambuco, the northeastern state where the team are based, since the "Immortal Fans" campaign began 13 months ago.
"I promise your eyes will keep on watching Sport," says Adriano dos Santos, a fan of the club who is awaiting a cornea transplant, in a video linked to the campaign which is backed by Brazil's health ministry.
"Your lungs will keep on breathing for Sport," says Luiz Antonio, a fan awaiting a lung transplant, while heart patient Marleide dos Santos adds: "I promise your heart will keep on beating for Sport."
More than 30 top sides actively encourage their fans to donate blood and several, including Corinthians, who last year beat Chelsea to win the Club World Cup, have put health messages or slogans on their strips.
One club, Victoria, replaced their red-and-black hooped shirts earlier this year with white-and-black hoops and only reverted to red when fans had donated a certain amount of blood.
Sport's campaign goes farthest and is certainly the most successful. Organ donations have increased 54 percent over the last year, helping to clear the long-standing waiting list for cornea transplants in Pernambuco.
"Overall, the number of people who are organ donors has gone up and the number of people waiting for organs has gone down," said Jacqueline Diniz, a nurse who leads the education campaign at the Pernambuco Transplant Centre. "This has been very important and had a huge impact."
The idea began last year with a brainwave from the Ogilvy advertising agency. The firm initially sought out Flamengo, the Rio de Janeiro side that has more than 30 million fans spread across Brazil.
Flamengo officials would not commit to the campaign so Ogilvy turned to Sport, a smaller club, but one whose fans are just as passionate.
"Sport loved the idea," said Marcela Lima, the club's Director of Marketing. "We understood that it is extremely important for a big club like ours to encourage and inform our supporters about how to save lives by being an organ donor."
The club ran advertisements at the stadium on match days and was given free media time by local radio stations, newspapers and broadcasters.
Celebrity supporters added their voices to the campaign and fans awaiting transplants took to the field with the team before some home fixtures.
Fans can sign up for the donor card at the club's stadium, print their own via the Facebook page, or request it by mail. The card comes in Sport's red-and-black colours with the club crest, and declares them "Sport Donor."
It informs family and medical professionals that the holder agrees to donate his or her organs after they die.
In Brazil, next of kin have the last word on whether or not to permit organ removal. In the past, more than four in five families have refused to let doctors take organs from relatives after death, according to Brazil's Health Ministry.
"Families have the final say so it is important for them to know," said Diniz. "Death is a traumatic event and many families want to see their loved ones remain intact but when they know the deceased has a donor card they respect their wishes."
The success of the programme has brought Ogilvy worldwide praise, including eight prizes at the prestigious Cannes International Festival of Creativity.
Now, company executive Paco Conde, who created the campaign, hopes to sign up other clubs and turn that success into more lives saved.
Millonarios of Colombia had asked to create their own donor card and an advertising agency in the United States was sounding out Major League Soccer clubs as possible partners, Conde said.
A lifelong Real Madrid fan, Conde said he was amazed at the fans' passion and their ability to put aside local rivalries for a good cause.
He even said he would be happy with a heart from a rival Barcelona fan if he ever needed a transplant.
"This isn't about one team," he said. "It's about us all. We want other teams to do it because the more teams that do it, the more lives we save."