Background: Effective online communication about the environmental risk factors of breast cancer is essential because of the multitude of environmental exposures and debate regarding the conclusiveness of scientific evidence. Purpose: The aim of this study was "to assess the content, readability, and cultural sensitivity" of online resources focused on the environmental risks factors of breast cancer. Methods: A purposive sample of webpages focused on environmental risk factors of breast cancer was obtained through a Google search using 17 search terms. Using nonparametric statistics, we assessed the content, readability, and cultural appropriateness of 235 webpages. Results: Eighty-two percent of webpages referred to research studies in their content. For the majority of sites, readability was at a high school reading grade level. Webpages were not explicitly intended for specific racial/ethnic groups. Discussion: Technical language and non-culturally specific messages may hinder users' attention to and comprehension of online breast cancer information. Additional research is needed to examine in-depth the accuracy of this online content. Translation to Health Education Practice: Findings suggest that collaborations between scientists, Health Educators, website designers/media professionals, and the community will be critical to the delivery of accurate, up-to-date, plain-language, and culturally sensitive information about breast cancer and the environment.