The new look goes live on 13 April at the London Marathon and will be supported by the relaunch of the Mencap website on 21 April. The charity's identity was created by branding agency Rare; its website has been overhauled by Public Life.
Mencap's marketing communications will focus on the barriers faced by people with a learning disability that stand in the way of getting on with everyday life.
The charity will also launch an enewsletter, called Be Mencap, which will be a key information tool in its marketing strategy.
According to a Mencap spokesman, about 1.5m people in the UK suffer from a learning disability and the issue directly affects more than 6m.