The agency's MediaCom Direct division will handle the business following a pitch against two other agencies including the incumbent, Tri-Direct.
Standard Life Healthcare sells private medical insurance policies, mainly under the Primecare name. MediaCom Direct's initial role is to grow its share of the personal medical insurance market.
The agency will work alongside the creative agency Response One, which creates Standard Life Healthcare's DM and third-party activity.
Anneliese Jones, the direct marketing manager for Standard Life Healthcare, said: "MediaCom Direct showed a strong understanding of the market and a highly focused, results-based approach."
Clive Howse, the deputy managing director at MediaCom Direct, said: "We will be working to optimise their use of traditional media while introducing some new and innovative direct sales channels."
Media planning and buying for Standard Life Bank, handled by Feather Brooksbank, is unaffected by the decision.