Lloyd Russell Moyle, a 32-year-old Labour MP representing Brighton, said he couldn't "keep quiet any more" that he was living with the virus - which he contracted when he was 22.
In remarks released before his announcement, he said: "Since then I have been on world-class treatment provided by the NHS - so I have not only survived, I've prospered, and any partner I have is safe and protected". "HIV in this country is no longer the death sentence it once was....tombs of the 1980s", he said.
"We have the ability to end new HIV transmissions as well as end stigma and discrimination, not only here, but globally, and I hope we can all make that our mission", he told fellow lawmakers, who gave him a standing ovation at the end of his speech, something hardly ever seen in parliament.
The Member of Parliament for Brighton Kemptown, who was elected in 2017, opened up about his HIV-positive status on the floor of the House of Commons on Thursday, two days before World AIDS Day.
One of those was Labour leader Jeremy Corbyn, who praised Mr Russell-Moyle for making a "brilliant and historic speech".
It was part of a campaign to raise awareness and encourage people to know their HIV status.
He said he had made a decision to speak out to help others seek treatment and fight the stigma surrounding the disease. "You walk out feeling totally numb, with a million things going through your mind, and at the same time a sense of absolute nothingness". He is the second MP to disclose that he is living...
Deaths from AIDS have fallen to the lowest level this century, with fewer than 1 million people dying from AIDS-related illnesses past year, it said.