The review covered all aspects of the Legion's fundraising activity including its core Remembrancetide recruitment campaign, donor development and promotion of its weekly poppy draw.
The charity has tasked Tangible, which has held the account since 1998, with broadening its audience base, particularly among younger audiences.
Guy Upward, head of direct marketing and legacies at Royal British Legion, said: "While the over 65s will remain important to us, Tangible demonstrated the possibilities that exist in other age groups, especially among the baby-boomer generation.
"The recent high profile of the armed forces and the recent conflicts in Iraq and Afghanistan present new opportunities for our brand, particularly through digital channels."
Nick Thomas, head of creative planning at Tangible, said: "This is a cause very dear to our hearts and we are delighted to retain the account.
"We've got some very exciting plans leading up to the Legion's birthday in 2011, including the recruitment of the millionth donor."