Mixu Paatelainen has left Kilmarnock with immediate effect to take over as manager of Finland, the Clydesdale Bank Premier League club have confirmed.
Assistant first-team coach Kenny Shiels will take control of team affairs following the departure of the 44 year-old.
Paatelainen is expected to be unveiled in his new position at a press conference later today.
A statement from Kilmarnock read: "Following careful consideration, Mixu has decided that the honour of managing his national team is one which he cannot refuse.
"He will take up his duties with the Finnish FA with immediate effect.
"Assistant first team coach Kenny Shiels will take charge of the club's preparations for its forthcoming matches."
Chairman Michael Johnston added: "I wish to record my personal thanks to Mixu for the manner in which he has conducted himself throughout his time at Kilmarnock, always positive, open to discussion and never complaining of any lack of resources, and to wish him every success in his new role as national team manager of Finland."
The former Dundee United, Aberdeen and Hibernian striker took over as manager of Kilmarnock in June 2010.
He had been out of football since leaving his role as Hibs boss the previous year.
Paatelainen took over a Kilmarnock side who had battled relegation in previous seasons and earned plaudits for the transformation at the club under his charge.
He was voted Clydesdale Bank Premier League manager of the month for December and leaves the Ayrshire outfit in fifth position in the SPL.
His efforts at Rugby Park did not go unnoticed and he was recently linked with a move to Scunthorpe United.
However, the lure of managing his national team proved too much to resist and he will take charge of his first match when Finland face San Marino in June.
Shiels was disappointed to learn of Paatelainen's departure but understood his reasons for quitting.
He said: "I've lost a good colleague.
"I'm disappointed on that front but I'm also happy for him that he can manage his country, which is a fantastic honour.
"It's a good moment for him."