The companies won the account after a competitive pitch process and will take over from 1 January 2016. Media planning and buying was previously managed on a local level by a number of companies worldwide.
The move forms part of VimpelCom’s strategy to globalise its operations across the group.
Rozzyn Boy, the chief communications and brand officer at VimpelCom, said: "We embarked on a transformation programme earlier this year, which aims to significantly improve our operational efficiencies, reduce our cost base and reinvent ourselves as a truly digital business.
"In a customer-first world, having the right digitally savvy creative and media planning partners is key to our marketing maturity and interactions with our valued customers."
VimpelCom operates in 14 countries, including Russia, Pakistan, Kazakhstan and Bangladesh, and is based in Amsterdam. It claims to be one of the world’s biggest integrated telecoms companies.
Both agencies will work across media planning and buying. SMG will cover Russia, Pakistan, Uzbekistan, Georgia, Ukraine and Kazakhstan, while Dentsu Aegis Network will be responsible for Italy, Kyrgyzstan, Tajikistan, Armenia and Bangladesh.
VimpelCom provides services under the Beeline, Kyivstar, WIND, Mobilink, Banglalink, Telecel and Djezzy brands and has more than 217 million mobile customers worldwide.