As a diabetic herself, Oscar winner and mom of Nahla, 3, Berry has a personal connection to the work of Diabetes Aware, which helps those with the disease manage it.
Oscar winner and mother of three, Roberts supports Hole in the Wall Gang Camp, for children suffering from cancer, sickle cell anemia, HIV/AIDS, and other diseases.
Supermodel and mother of four, Klum assists the Elizabeth Glaser Pediatric AIDS Foundation, providing HIV prevention and treatment for women, children, and families.
The Cougar Town star and mom of Coco, 6, is an advocate for OmniPeace, an L.A.-based fashion brand. It donates profits to promoting peace, human rights, and education, and to ending poverty in Africa.
After being diagnosed with breast cancer in 2008, Applegate created Right Action for Women, a foundation that educates women about breast cancer and provides aid to those who can't afford insurance to cover screenings.
She plays a desperate housewife on TV, but she's also joined forces with Feeding America, which distributes food through a nationwide network of food providers and seeks to increase public awareness about the issue of hunger in America.
Lopez created The Maribel Foundation, funding telemedicine clinics connecting children in underprivileged communities with top pediatric specialists.
Oscar winner and mother of two, Witherspoon serves as honorary chairperson of the Avon Foundation, a nonprofit that tackles breast cancer and domestic violence.
This star lends a hand to Milk + Bookies, where children select, purchase, and inscribe books that are donated to peers who don't have books. Garner has two daughters, Violet, 5, and Seraphina, 2.
When Heigl was a kid her older brother died in a car accident and her family donated his organs. Heigl now works with Donate Life America to inspire people to sign up to be organ donors.
The singer and new mom is a cofounder and global ambassador for Keep a Child Alive. The organization provides treatment and support to children and families affected by HIV/AIDS in Africa and India.
Originally published in the May 2011 issue of Parents magazine.