They are Starcom, Walker Media, Initiative and MediaCom. MediaCom, the incumbent agency, has held the account since 2000.
Meetings will take place in November with a result expected before the end of the year. The pitch will be led by COI's deputy chief executive, Peter Buchanan.
Starcom already works with COI - it took over the £20 million radio planning and buying contract from OMD UK in June.
Starcom Mediavest held COI's TV buying contract until April, when Carat won the £70 million account after a two-month pitch.
Jeremy Found, COI's head of media, said: "The standard of applications was very high and the four agencies were selected on the strength of their submissions."
COI's cinema buying contract, held by Universal McCann, is under review.
The government communications organisation is also reviewing its strategic media planning roster. The incumbents include Naked, Starcom, PHD and Ingram.
Earlier this year, COI renewed its creative roster. Agencies including Wieden & Kennedy and Clemmow Hornby Inge were appointed to the £156 million account.