In a statement released today, the charities said they believed they could achieve more together than apart in ensuring everyone with a breast cancer diagnosis gets the support they need to combat the disease.
The merger, which will be completed on 1 April, will involve both charities operating as separate brands initially, with a new logo and name expected late next year.
Delyth Morgan, chief executive of Breast Cancer Now, will be the new organisation’s chief executive, with Samia al Qadhi leaving her position as chief executive of Breast Cancer Care on 31 March.
The chair of the new charity will be Jill Thompson, who is currently treasurer for Breast Cancer Care.
The new charity’s board will be made of six trustees from each of the two charities, and at least one-third of the trustees will have personal experience of breast cancer, the charities said.
Breast Cancer Now had an income of £28.3m in the year to 31 July 2017 and spent £29.9m. It employs 156 people, according to the Charity Commission’s website.
Breast Cancer Care had an income of £16.9m and spent £16.4m in the year to 31 March 2017, and has 215 employees, the Charity Commission’s website says.
This is Breast Cancer Now’s second merger in four years. The organisation is the product of a merger between Breakthrough Breast Cancer and Breast Cancer Campaign.
In a statement, BCN said the opportunity to merge with Breast Cancer Care "did not exist" at the time of the creation of Breast Cancer Now, which was why it was taking place four years later.
Morgan said: "As the UK’s first comprehensive breast cancer charity, we will be driven forward by collaboration, ambition and – most importantly – the passion of our supporters and partners, who will remain at the heart of the new organisation.
"By joining forces, we’ll do everything we can to make the research breakthroughs that will give women more time to live and to ensure everyone affected by the disease has the support and care they need. We look forward, with great hope, to taking this exciting step together."
Al Qadhi said: "Uniting will now make it possible to reach a future sooner where everyone affected by breast cancer lives and receives the support they need to live well.
"Delyth brings incredible passion and expertise and will be a wonderful leader of the new charity to, importantly, speak with one clear voice for people affected by breast cancer, both now and in future."