Smart is the Philippines' largest wireless company as well as being one of the top five advertisers, with an estimated annual spend of P1 billion (about US$18 million).
Ace Saatchi was the incumbent agency, which handled the business for the past four years. Ace will continue to handle creative assignments along with DDB, FCB and BBDO Guerrero Ortega.
OMP chairman Antonio Samson said Smart was looking for "stronger research".
"Smart was looking for an alternative. It wanted a stronger research component, effective tracing and monitoring of ads and market information, and defining the characteristics of the market it is trying to target.
It also helped that DDB (Optimum Media's sister company) is one of its creative agencies," Samson said.
Smart offers the market wireless phone connection, mobile call and text messaging cards, among other products. Smart and rival Globe Telecommunications are in a fierce battle for a share of the rapidly-expanding market. Smart's market edge is its ability to connect phone users even in the remotest parts of the country.
Optimum Media executive vice-president and managing partner Ador Perez will head the media agency's team servicing Smart.
OMP was established in July 2003 to offer full-service media capabilities including research and monitoring tools for measuring advertising effectiveness.
Part of its mission is providing full transparency and accountability for every peso that is invested by its clients on media.