Experts say it is too early to describe them as â€˜curedâ€™ â€“ but the Aids virus shows no signs of returning in either patient.
The men, who had HIV for about 30 years, received transplants to treat blood cancer several years ago. One stopped taking anti-HIV drugs four months ago, while the other stopped seven weeks ago.
Their US doctors say keeping them on the drugs after their transplants first took place prevented their new supplies of healthy blood cells from becoming infected by HIV. The patientsâ€™ old, diseased cells were then attacked by the new ones.
The International Aids Society conference in Malaysia heard that now, even though the patients have stopped taking antiretroviral drugs, the virus cannot be detected in their blood. Normally, the disease can only be kept under control with lifelong treatment.
Working out why the bone marrow transplants had such a strong effect could lead to new treatments for the 34million living with Aids. An estimated 100,000 Britons have HIV, including 20,000 who have not been formally diagnosed.
Timothy Henrich, of the Brigham and Womenâ€™s Hospital in Boston, said the men â€˜are doing very wellâ€™, but warned: â€˜While these results are exciting, they do not yet indicate the men have been cured. Only time will tell.â€™