Bob Arum says he will not have any professional dealings with Daniel Kinahan again.
The Top Rank boss is co-promoter of heavyweight champion Tyson Fury, to whom Kinahan has been an advisor.
Arum previously called Kinahan 'an honourable man'.
Kinahan founded MTK Global in 2012, which represents a number of boxing's top fighters.
He was sanctioned yesterday by the US government and named as part of an organised crime group accused of smuggling cocaine.
Arum says he will honour the sanctions that have been imposed by the US Government upon Kinahan and his connections.
"I will not do business with Kinahan and based on these assertions by the US Government, I don't believe that somebody who is implicated in drug trafficking should be involved in boxing, and particularly shouldn't be involved with my company Top Rank in any capacity."
