Mark Fielding, the chief executive of ISME, has announced he is leaving the small and medium sized business organisation at the end of the month.
An accountant, Mr Fielding has been at ISME for the past 15 years.
He will be replaced by General Manager of the Freight Transport Association Neil McDonnell.
"It has been my privilege to share in the rich and wonderful ISME legacy and to serve as the CEO," Mr Fielding said in a statement.
"It has also been my privilege to be involved with such fine business people who show a loyalty to ISME and to each other," he added.