The vast majority of HIV patients taking the latest combination treatments survive at least a decade, say researchers.
Modern combinations of drugs have cut HIV deaths
Trials across several European countries found death rates from Aids have fallen by 80% since 1997, when the regime was introduced.
Older people infected with HIV no longer have a reduced life expectancy compared with the young.
The 10-year mark is an arbitrary one - but important to HIV researchers who use it to compare the success of drugs to suppress the virus.
In this case, the fact that most patients are surviving beyond a decade demonstrates beyond doubt the vast improvements that the latest therapies have delivered.
And although firm evidence is not yet to hand, it implies that many patients could live far beyond their first 10 years with HIV, particularly if the drugs continue to improve.
More than 50,000 people in the UK are living with HIV, and "highly active antiretroviral therapy" (HAART) is the most advanced method of attacking the virus, even though it cannot cure the infection.
When the combination of drugs was first introduced, death rates immediately fell by half.
Initially, only one in five people were given HAART, but that has risen swiftly as the impact of the drugs became apparent.
However, it is only now that the effects of HAART on lifespan of HIV patients can be measured and assessed.
Compare and contrast
Scientists at the Medical Research Council's Clinical Trials Unit in London assessed the results of 22 different studies across Europe, Australia and Canada, and confirmed the effects of the introduction of HAART were the same everywhere.
The results were published in the Lancet medical journal.
Dr Kholoud Porter, who led the analysis, said: "The introduction of HAART has been a tremendous success.
"Before this therapy was introduced, about half of those infected were expected to live for ten years after diagnosis, much less if they were, say, 40 years old when infected.
"Now, people treated with these combinations of drugs can almost all expect to live at least 10 years after diagnosis, regardless of their age at infection.
"However, our findings do point to the importance of an early diagnosis so that people can access the best treatments at the right time.
"We also need to continue to explore what happens when therapy starts to fail, for example due to resistance to antiretroviral drugs, if we are to maintain improved life expectancy for people living with HIV."
Julian Meldrum, from Aidsmap, told the BBC that there were some grounds to hope that the drugs would keep on working well into the second decade after diagnosis - although little evidence to confirm this is yet available.
He said: "The good news is that it appears that so far the effects of HAART are not wearing off.
"In future, the drugs will improve yet further, and there should be fewer side-effects, making it easier to adhere to the therapy.
"There are certainly grounds for optimism."
However, he said: "There are still some HIV patients in the UK who have unequal access to these treatments - mainly in the refugee and migrant communities.
"And the study shows that injecting drug users who are infected with HIV this way are still more likely to die than people infected through sexual contact."
Martin Kirk of Terrence Higgins Trust said: "We must remember that of all the people who will die this year with AIDS-related illnesses, a third will do so just three months after diagnosis.
"This is because they tested too late for treatments to be effective.
"There is still work to be done to encourage people to test for HIV, and remind them that it neededn't be a death sentence."
The success of HAART in the developed world increasingly highlights the gulf between these countries and those in the developing world, where access to any form of antiretroviral drugs is often almost impossible.
Last year, the number of people worldwide infected with HIV reached more than 40 million.