The Workplace Relations Commission has ordered RTÉ to pay €50,000 to former employee Valerie Cox because the broadcaster discriminated against her on age grounds.
Ms Cox had two separate contracts of employment with RTÉ, with two separate sets of terms and conditions.
The first, dating from August 2004, was a full-time contract of direct employment, which involved work as a radio reporter on progammes including Today with Sean O'Rourke.
That contract terminated on 8 March 2016 when she reached the age of 65.
The second contract, which commenced in August 2003, was a casual or irregular contract to do "It Says in the Papers" for which she was paid a daily rate.
The evidence was that she would be rostered for one week every six weeks but that "there was nothing definite".
Ms Cox told the WRC adjudication hearing that in March 2016, after her full-time contract was terminated, she was told that she would continue to be placed on the roster for the casual/irregular contract but that "A period of time would have to elapse between her retirement from her full-time position and being placed on the roster again in relation to this contract".
Ms Cox went abroad for some months, but when she returned she was told that she would not be allowed to come back as her contract had ended.
She argued that she still had a casual/irregular contract and that while her full-time contract had terminated in March 2016, it was only in December of that year that she was informed that the casual contract had also been terminated.
The WRC heard that there were a number of people rostered on this programme, of whom two were over 65.
RTÉ argued that the retirement age for the complainant was clearly set out in their terms of employment in the associated handbook, and that Ms Cox had taken part in a pre-retirement course in October 2015.
The station also said their compulsory retirement age of 65 was designed to encourage a high staff retention rate by creating opportunities for promotion and intergenerational fairness, as well as ensuring the renewal of employment teams.
RTÉ also argued that the compulsory retirement age recognised the dignity and respect due to all employees and avoided disputes regarding capacity and underperformance.
The Adjudication Officer said it seemed clear that the staff handbook does provide for working beyond 65 years, "at least in relation to this category of employee".
She also noted that the staff manual provided for "working after normal retirement age" and did provide for a once-only fixed-term contract to be given to an employee after the age of 65, with the duration of any such contract unspecified.
She found that RTÉ had not established that its compulsory retirement age was objectively justified, and ruled that Ms Cox had been discriminated against on the basis of her age in relation to the termination of her casual/irregular contract of employment.
Ms Cox said she had loved working for RTÉ, which had been a good employer, but had taken the case because she was concerned about ageism in Ireland.
She felt it was unjust that she should have to retire at 65 and the WRC had vindicated that view.
RTÉ said it did not comment on individual cases. It is not yet known if it will appeal the ruling.