Sex workers were previously barred from donating but they will now be allowed to give blood three months after they last had sex.
Men who have sex with men were only allowed to give blood 12 months after their last sexual activity but that will now be reduced to three months.
Scientists now say that a virus or infection will be picked up in blood tests within three months of infection, leading to the new rule that relaxes blood donor restrictions for 'at risk' groups.
The rule changes will come into force at blood donation centres in Scotland in November, and in early 2018 in England.
The move has been praised by experts as a triumph for science over prejudice and stigmatization.
Fears over infections being passed on through donations from gay men led to an outright ban at the height of the Aids epidemic which sparked complaints about prejudice as testing accuracy has improved for all donor blood samples.