Cascaid will data mine into Macmillan's existing database to generate different audience profiles such as donors, event participants and volunteers.
A mix of qualitative research through focus groups and one-on-one interviews will then be used to gain further information about the groups to determine connections with the Macmillan cause.
Finally, hard data will be linked with the qualitative data to build new intelligent marketing models.
Judith Dutton, director of fundraising at Macmillan Cancer Relief said Cascaid's work would determine how the charity develops its communications strategy.
"We want to really understand our supporters -- what they expect from us, what they want to know about our work, how they want us to communicate, which channels and formats are most useful to them and what will inspire them to continue their support.
"Cascaid's work will be instrumental in determining how we move forward with our communications in a more personalised and informed way," Dutton said.
Roger Lawson, Cascaid director, said: "Too many organisations continue to offer wholesale communications that push the charity's broad messages rather than offering the donor what they personally are interested in.
"Macmillan has varied audiences and recognises that, in order to truly motivate all of them, it needs to firstly understand them."
Cascaid won the business after a competitive pitch on the strength of the agency's data serives and experience of dealing with fundraisers.
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