Breast cancer is the most common cancer in Pacific Islander women, yet relatively little is known about their cancer risks and screening behaviors. Chamorros are indigenous people from Guam, and California is home to the largest numbers of Chamorros on the mainland United States. This study examined the breast cancer risk, knowledge, and screening behaviors in a nonprobability sample of Chamorro women age 40 years and older in Los Angeles and Orange Counties (n = 227). The proportional incidence ratio for breast cancer among Chamorro women was found to be 0.7 compared with white women in California, indicating a lower current breast cancer risk for Chamorro women compared with white women. Thirty-seven percent of respondents ever performed a breast self-examination (BSE), 93% ever had a clinical breast examination (CBE), and 77% ever had a mammogram. In terms of screening maintenance, only 27% did BSE monthly, 66% received a CBE in the past year, and 25% received yearly mammograms. Significant correlates of CBE were higher educational attainment, married status, higher income, and health insurance coverage. Women who knew of breast cancer symptoms, would undergo treatment, and would like to know if they had breast cancer were also more likely to have ever had a CBE. With regard to mammography, older age, moderate income, married status, and use of traditional healers and healing practices were associated with higher screening incidence. Implications of these findings for developing culturally tailored and appropriate cancer screening programs are discussed.