The Leaving Certificate exam has been postponed, Education Minister Joe McHugh has confirmed.
Some 61,000 students in the Republic were due to sit the exam on July 29.
"Unfortunately there is now compelling advice that shows holding the exams and returning to school would be impossible."
Under the revised plans, a system of predictive grades will be given to students in lieu of them sitting physical exams.
Speaking at Government Buildings today, Mr McHugh said Covid-19 has forced the government to make changes that would have been unthinkable previously.
The education minister also said a special unit in his department has been designed to oversee and apply a "nationalised standardisation" to Leaving Cert predictive grades.
Mr McHungh said students will have the option to appeal over their grade if they are not happy.
"My preference was for the exams to be proceed. However, proceeding with the exams this summer would have been unfair given the current pandemic."
Mr McHugh said it is expected students may receive their results in August or "as close to the normal date as possible".
He added: "We can't put a specific date on when students will get their Leaving Certificate results."
The Children's Ombudsman, Dr Niall Muldoon, welcomed the decision, saying: "Some 61,000 students have faced considerable uncertainty surrounding their exams over the past number of weeks and months and I am glad to see a final decision being made.
"I appreciate it was not an easy decision to make and many young people will be disappointed, but ultimately, I support today's decision and believe it has been made in the best interest of young people throughout Ireland.
"It is up to us all now to support students in the alternative arrangements and ensure they go on to the next stage of their education, or the first stage of their working lives, with confidence."