Two adults have been confirmed with the Zika virus, health chiefs have said.
The cases – the first of their kind in the country – are unrelated to each other and both patients are said to be currently well and fully recovered.
Both individuals have a history of travel to a Zika-affected country, the Health Service Executive (HSE) confirmed.
“These are the first cases of Zika virus infection confirmed in Ireland,” a HSE spokeswoman said.
“Neither case is at risk of pregnancy.”
The HSE said the newly discovered Zika cases are “not an unexpected event” as many other European countries have reported cases as a result of people travelling to affected areas.
Health chiefs have urged people who fall ill within two weeks after returning from an affected area to seek medical help.
The news comes as the first known case of the Zika virus being sexually transmitted in the United States has been reported.
The US Centres for Disease Control and Prevention said a patient in Texas had been infected with the virus after having sexual contact with an ill person who returned from a Zika-affected country.
The virus is usually spread through mosquito bites, but investigators have been exploring the possibility it can also be spread through sex.
The virus was found in one man’s semen in Tahiti, and there was a report of a Colorado researcher who caught the virus overseas and apparently spread it to his wife back home in 2008.
The World Health Organisation has declared an international emergency over the virus, which is linked to birth defects in Brazil and the Americas.