Eventia members were 94% in favour of the merger, while 93% of IVCA members voted for the proposal.
Simon Hughes, Eventia chairman said: "This is the conclusion of a long journey for Eventia, that actually started when Mark Saxby was in my post and Izania Downie was still our CEO. They responded to the concerns raised by event industry leaders about the fragmented nature of the sector and the need to embrace new and emerging digital platforms that would radically alter the way we work across the events world."
"This positive endorsement of a merger with the IVCA puts us in a much stronger position as an integral part of the creative communications sector. I'm delighted that our members have supported this, as it demonstrates once again their appetite for progress and willingness to embrace the challenge of change."
Marco Forgione, CEO of the IVCA, added: "This is a really exciting moment for both associations and both our management teams are really looking forward to blending our talents to further improve the range and quality of the services we offer our members."