The Anchorman actress, who won her battle with breast cancer in 2008, will open Right Action Launch for Women in September.
The charity aims to help at-risk women who cannot afford to take the correct preventative measures.
The 38-year-old told WENN: "It's a programme giving financial aid to high-risk women who can't afford to get MRIs, which is how I found my cancer.
"It's unfortunate that insurance companies [in America] don't cover the cost of that. It's such an incredible device because you can find it at an early detection stage. We started our pilot programme and started helping women already, even though we aren't launched.
"The other aspect of the programme is to do genetic counselling and help women understand what being high-risk means, and understanding what foods are good for their bloods and how to prevent this disease from happening. That has been my mission."
Applegate recently announced that she was pregnant with her first child.
