The Dentsu Aegis Network agency Vizeum holds the £14 million business in the UK and has worked with AB InBev Russia, which is included in the review.
ZenithOptimedia also works with the brewer on part of the Russian business.
Agencies including Havas Media and combined Publicis Groupe teams work in other European countries.
The review is expected to last several months. Vizeum, which won the UK account in 2010, is defending its business.
A spokeswoman for AB InBev said: "AB InBev periodically evaluates its marketing services organisation to ensure that we maintain the best working relationships and optimise the use of our marketing spend with the best agency partners."