The agency will develop an integrated idea to raise awareness of the work Marie Curie Cancer Care carries out.
The agency will deliver a through-the-line campaign with the aim of differentiating Marie Curie against other cancer charities such as Macmillan Nurses and Cancer Research.
Greg Delaney, chairman of DLKW, said: "Marie Curie Cancer Care provides a fantastic, important service in providing help to terminally ill patients and their families. It will be our job to help them publicise this, and we're really looking forward to working with them."
Marie Curie Cancer Care provides cancer patients with care at the end of their lives. The charity wants to inspire people to give their time and money to support the 2,000 Marie Curie Nurses working in communities across the UK.
Chris Dainty, director of PR and marketing at Marie Curie Cancer Care, said: "Most of us want to be cared for at home at the end of our lives -- and Marie Curie nurses make that wish a reality. DLKW will be helping us raise awareness of the issues around end-of-life care and ensuring more people know about the work of our nurses."
Incumbent Maher Bird Associates, which has worked with the charity for 10 years, was knocked out an earlier stage of the pitch process.