One-third of women worrying about breast cancer report impaired ability to function daily. It is unclear whether women who worry about breast cancer would experience more sleep problems than those who do not. Data were obtained from a cross-sectional study of black and white women to investigate the association between breast cancer worry and insomnia complaints. Several questionnaires were administered during face-to-face interviews to elicit health and sociodemographic data. The present analyses focused on black and white women (n = 1,038; age range = 50-70 years) with no cancer antecedents or history. Overall, 62% of the women worried about breast cancer, and 49% reported insomnia complaints. Logistic regression analyses, adjusting for effects of age, ethnicity, family history, and perceived risk of developing breast cancer, yielded an odds ratio for insomnia complaints of 1.52 (95% CI: 1.15-2.02, p < .001) among women reporting breast cancer worry. More than one half of the women worrying about breast cancer were likely to report insomnia complaints, notwithstanding the fact that those women did not have a history of cancer. Although fewer black women reported breast cancer worry and insomnia complaints, they were as affected as white women by the impact of worry on mood and daily activities.