ABSTRACT Objective: To evaluate the knowledge and practices of gynecologists, obstetricians, and family and community physicians in Brazil regarding breast cancer screening, mammographic findings defined by the BIRADS™ system, and their approach to suspected clinical lesions. Methods: This was an observational, cross-sectional, descriptive study conducted using an online research questionnaire distributed via email to 9,000 gynecologists and obstetricians and 5,600 family and community and preventive medicine doctors actively practicing in Brazil. Results: Among gynecologists and obstetricians, 42.8% follow the 40-74 years screening, 33.5% follow the 50-69 years screening, and 23.6% do not follow any specific protocol. Among the family and community physicians, 76.6% follow the 50-69 years screening protocol, and 23.4% do not follow any specific protocol. When we evaluated the responses regarding the behaviors of each BIRADS™ classification, 46.3% of responses were wrong among gynecologists and obstetricians, and 77.9% were wrong among community and preventive medicine doctors, exhibiting a significant difference. The role of breast ultrasound in screening was evaluated; 39.1% of gynecologists and obstetricians and 20.3% of community and preventive medicine doctors consider it as a screening method. Among gynecologists and obstetricians who do not follow any screening protocol, 94.7% consider ultrasound as a screening method. Among community and preventive medicine doctors, only 26.5% of physicians who follow the 50-69 years screening method consider it as a screening method. Conclusion: Inadequate training results in gynecologists and obstetricians, and family and community physicians performing inadequate screening and not following the recommended practices outlined in the BIRADS™ system. Objective BIRADS system lesions Methods observational crosssectional, crosssectional cross sectional, sectional cross-sectional 9000 9 000 9,00 5600 5 600 5,60 Results 428 42 8 42.8 4074 40 74 40-7 335 33 33.5 5069 50 69 50-6 236 23 6 23.6 protocol 766 76 76.6 234 4 23.4 classification 463 46 3 46.3 779 77 77.9 difference 391 39 1 39.1 203 20 20.3 947 94 7 94.7 265 26 26.5 Conclusion 900 00 9,0 560 60 5,6 42. 407 40- 33. 506 50- 2 23. 76. 46. 77. 39. 20. 94. 26. 90 0 9, 56 5,