Ryan Tubridy has lost 110,000 listeners since replacing the late Gerry Ryan on radio.
The latest radio listenership ratings reveal that the host of the 2fm mid-morning show has shed the most listeners.
He lost another 16,000 listeners since the last Joint National Listenership Research (JNLR) figures were published in May.
Prior to that another 14,000 switched off between February and May. Now just 186,000 listeners tune in to 'Tubridy' on weekdays between nine and 11am. That compares with 296,000 listeners in May 2010.
Yet despite the loss of almost a third of Ryan's old audience since taking over the slot last September, RTE last night said it will plough ahead with the 'Tubridy' show.
RTE head of radio Clare Duignan also defended the figures, saying: "Tubridy has found its rhythm." But leading media buyer Craig Farrell, managing director of Starcom, said the 'Late Late' host had failed to captured listeners' imagination in the same way Ryan did.
"He's just different," Mr Farrell told the Irish Independent last night.
"It was always an inevitability that he would lose listeners. Gerry Ryan was the cash cow for 2fm." he said.
"I don't think he's lost his style but, personally, I think his future lies outside Ireland."
Ryan, who is standing in for Graham Norton on BBC Radio 2 over the summer, was unavailable for comment last night.
And while Today FM's Ray D'Arcy lost 6,000 listeners, he continues to lead the ratings in the mid-morning chat show market with 212,000 listeners.
However, D'Arcy's colleague Ian Dempsey didn't fare so well losing 14,000 listeners on his breakfast show.
The biggest winner in the ratings' war was RTE Radio One which won 6,000 new listeners to its evening 'Drivetime with Mary Wilson', followed by the easy listening 'Ronan Collins Show' which gained 5,000 listeners.