ISES UK has 250 active members, while MPI has 324 members in the UK.
The chapters will work together to promote their events and encourage members to attend each other’s events, as well as running joint activities.
MPI UK and Ireland president Fiona Pelham said the bodies would remain independent, despite the push for collaboration.
"Both MPI and ISES have a strong international background and they would never merge," she said. "We realised people have many pressures on their time and when you become a member of an association it should be about that body giving you what you need, when you need it."
She added that one of the key aims in 2011 would be to assist members in becoming "leaders in the industry".
In addition, the executive boards of each association - comprising president, immediate past president and president-elect - will meet on a quarterly basis to discuss opportunities to work together and expand the associations.
ISES UK president Richard Foulkes said: "ISES represents people involved in creative event marketing activity while MPI represents the professional and event planning sector; in our view these are two very complementary associations. ISES sees this collaboration as a way of continuing to demonstrate value to our membership, providing even more quality education and a greater network for our members to connect and be inspired."