The charity has historically used only direct marketing channels to encourage legacy funding, which makes up close to half of its income.
It will target the over 60s with the aim of driving awareness of legacy giving. Only four per cent of the population currently leaves a legacy to charities in their will.
"It's vital that we do all we can to optimise this particular source of funding and help sustain and improve the work we carry out," said Duncan Bell, head of legacy marketing at Cancer Research UK.
The campaign will be through incumbent agency WWAV Rapp Collins, which has worked on previous legacy marketing activity using below-the-line channels.