Head coach Sean Holley and Australian director of coaching Scott Johnson have both quit the Ospreys with immediate effect, the Welsh regional rugby side says.
Holley has been with the Ospreys since their inception in 2003 while Johnson had been due to stay with the club until the end of the season before joining the staff of Scotland boss Andy Robinson.
Johnson, 49, who has struggled with a debilitating ear condition, said he would be returning to Australia "to get over the illness that I've suffered with over the last two years, before taking up the post with Scotland at the end of the season".
Former Ospreys back-row Steve Tandy takes over as head coach aged just 32.
It appears Holley has paid the price for the club's lack of success in the European Cup, where they reached the quarter-finals in 2010, losing to French side Biarritz, but have since failed to qualify for the knockout stages.
"Professional sport is a fast-moving and ever-changing environment and after nine years in office we feel that the time is now right to freshen things up and look at alternative options," Ospreys managing director Mike Cuddy said.
Johnson, a former Wales and Australia skills coach, who quit as coach of the United States to join the Ospreys three years ago, said he had offered to stand down when he announced he would not be renewing his contract in December.
"But they (the Ospreys board) felt that it would be better for the organisation if I remained in office to help provide some stability during what was inevitably going to something of a transitional period," Johnson explained in a club statement.
"Since then we've been in constant dialogue and six weeks down the line, we've agreed that the time is right for me to move on so we've shaken hands and I'm walking away early from the remainder of my contract.
"For me personally, the next few months will allow me to head back to Australia to catch up with my family and to get over the illness that I've suffered with over the last two years, before taking up the post with Scotland at the end of the season."
The Ospreys, formed out of a merger between the professional sides of Neath and Swansea, historically two of Wales' strongest clubs have, for all their European struggles, won three Celtic League titles, the last two years ago.
They are now second in the table of this season's tournament for leading clubs from Wales, Scotland, Ireland and now Italy.
"The Ospreys will always be my home region," said Holley, who succeeded Lyn Jones as head coach in 2008.
"It's going to be a very different way of life and a difficult one at first. I guess I've become part of the furniture.
"However that has also become part of the issue ... I am still only 41 and so I feel I've got a lot to offer."
