We are bitterly disappointed to lose Mike McCarthy
Mike McCarthy has announced his intention to leave Connacht at the end of the current season.
McCarthy's contract expires in June next year and, following lengthy negotiations, Mike has decided to join Leinster.
Chief Executive Tom Sears said: "We are bitterly disappointed to lose Mike McCarthy, who has been a popular senior member of our squad.
"While disappointed, particularly given the continued success of Connacht in recent years, we respect the individual player's decision and wish Mike every success in his future playing career."
Connacht has seen significant success in recent years both on and off the field.
With a growing fan-base and record match attendances, Connacht has enjoyed notable victories in the last 12-months over European Cup heavy hitters Biarritz and Harlequins, and over both Leinster and Ulster in the Pro12.
Tom Sears explained "We have been aware of Leinster's interest in Mike for some time. It is disappointing they have persistently targeted Connacht players in recent years, particularly when often not in the best interest of Irish Rugby."
Connacht has recently strengthened its playing squad with the arrival of experienced professionals like Dan Parks and Nathan White, who together with existing senior players have assisted the development of a crop of talented indigenous young players. Connacht will continue to work with the IRFU to find a world-class replacement for Mike and to further build and strengthen our squad, with a view to delivering more success for Connacht.