New policy comes into immediate effect if criteria met.
The lifetime ban on gay men donating blood has been lifted in Ireland.
Health Minister Simon Harris stressed the importance of people offering blood and offered assurances that necessary programmes and procedures were in place to protect both donors and recipients of blood and blood products.
A relaxation of donation policies for men who have sex with men followed a two-year consideration by the Irish Blood Transfusion Service and was approved by the minister last June.
Harris said: “Only 3% of the eligible population of Ireland are active blood donors – yet 1 in 4 people will require a blood transfusion at some time in their lives.
The ban in the Republic is being replaced by a deferral period for men who have sex with men. They will be allowed to give blood one year after they last had sex.
It follows a similar move in Northern Ireland last year. The change to policy, announced by health minister Michelle O’Neill, brought the north into line with England, Scotland and Wales.