The American Cancer Society played key roles in organizing and participating in a major conference on breast cancer in the developing world November 3-5 at Harvard University in Boston, Massachusetts. The aim of the conference, which was called Breast cancer in the developing world: meeting the unforeseen challenge to women, health, and equity, was to raise greater global awareness of the epidemic of breast cancer in low- and middle-income countries, where the disease is now the leading cause of cancer-related death among adult women. American Cancer Society Chief Executive Officer John Seffrin, PhD, spoke to the global health leaders attending the conference about the lessons of tobacco control and how these lessons can help the breast cancer movement. Additionally, Alessandra Durstine, vice president, Regional Strategies and director, Latin America Programs, American Cancer Society; and Robert Smith, PhD, director of Cancer Screening, American Cancer Society, discussed advocacy planning and population-based screening. Durstine also represented the American Cancer Society on the steering committee for the event. The conference brought together delegates and speakers from around the world who are working on breast cancer, including leading researchers, policy-makers, and advocates. More than 10 cancer control nongovernmental organizations from Africa, Asia, and Latin America, which are partners of the American Cancer Society, participated in the conference.