Objectives:Regular screening for breast cancer is associated with better survival, but compliance with guidelines depends on good knowledge and attitudes. This study aimed to assess the level of breast cancer knowledge, attitudes and screening practices in Lebanese females, and identify their socio-demographic determinants as well as barriers to mammography use.Methods:This cross-sectional study was conducted with 371 Lebanese females residing in Beirut aged 18-65 with no history of breast cancer. The questionnaire applied was adapted from Stager and Champion. The overall knowledge score was determined with sections on general knowledge, curability, symptoms, and screening; the overall attitude score concerned attitudes towards breast cancer, screening, and barriers; and the overall practices score was for breast self examination (BSE), clinical breast examination (CBE) and mammography. Bivariate and multivariate analyses of socioeconomic determinants were performed for each score.Results:The mean knowledge score was 55.5±17.1% and that for attitudes was 71.9±8.3%. For self-examination, mammography and clinical examination practices, individual means were 45.7±42.3%, 77.9±36.5% and 29.1±45.5%, respectively. Knowledge, attitudes and practices correlated positively with each other (p<0.0001). The highest average was the knowledge of symptoms (72.8±24.7%), and the lowest that of curability (49.6±25.7%). Most frequent barriers to mammography were fear of learning bad news, pain, costs, and staff unpleasantness. Higher education was associated with better knowledge (p=0.002) and smoking with lower levels (p=0.003). Older age (p=0.002), higher education (p=0.02), and taking exercise (p=0.02) were associated with better attitudes. Higher education (p=0.02) and having children (p=0.003) were associated with better practices.Conclusion:More emphasis should be placed on educating females on the curability of breast cancer and specific targeting of the barriers identified.