Caroline Gray is to leave her role as general manager of Fairyhouse racecourse.
Gray, who joined the Irish Horseracing Authority in 2000, will not return to work at the end of her current period of maternity leave.
Peter Roe will continue in his role as acting general manager.
Gray said: "I have really enjoyed my 11 years working in the horseracing industry.
"However, I feel the time has now come to move on and in particular to spend more time with my young family.
"I would like to acknowledge the support of all those in the industry with whom I came in contact over the years and in particular my work colleagues in HRI and Fairyhouse."
Brian Kavanagh, chief executive officer of Horse Racing Ireland, which owns Fairyhouse as part of its racecourse division, said: "I would like to thank Caroline for the significant contribution which she has made to Irish racing and offer her every good wish for the future.
"Pending an overall review of our racecourse structures, Peter Roe will continue as acting general manager at Fairyhouse, and Nessa Joyce will continue in the same role at Tipperary."
