The agency will help Admiral look to replace its Russian dolls ad which has been running since 2010. A new campaign is planned for early 2016.
Admiral contacted agencies to discuss its creative strategy in January, and held pitches in March.
It has worked with just one agency in the past – the Gate (then known as Chick Smith Trott) which picked up the account in 2010.
Fanny Limare-Wolf, the deputy marketing director at Admiral, said: "In the past we have largely handled our advertising creative in-house, but feel that now is the time to utilise the skills and experience of external practitioners to assist us in a brand new TV campaign.
"We appointed McCann because they have demonstrated great creativity and understanding of our business during the pitch process."
Jon Marchant, the managing partner at McCann Birmingham, said: "With all the well-documented negative pitch processes we have seen recently, it was refreshing to engage with a client team possessing such professionalism, and where genuinely original and clever creativity was the winner of the day."