Background: Breast cancer is the most common cancer among women in Jordan and on average 70% of thecases present at advanced stages. The aim of this study was to assess the effectiveness of a public educationalcampaign conducted by the Jordan Breast Cancer Program to improve breast health knowledge among Jordanianwomen and to relate their knowledge to breast health practices. Methods: The campaign was conducted in fivegovernorates in Jordan with a total of 105 public group lectures about breast cancer focusing on early detection.The total number of participants was 2,554 women with a median age of 37 years (range: 15-73 years). Mediannumber of women per lecture was 24 (range: 9-38). Before the lectures, the women answered a structuredquestionnaire about their knowledge and practices. After the intervention 2,418 of them filled a post-testquestionnaire with the same content. Correct answers on the 15 knowledge questions yielded a maximum scoreof 15. Determinants of breast health practices were identified using multivariable logistic regression analysis. Results: The mean knowledge score increased significantly from 10.9 in the pre-test to 13.5 in the post-test(p<0.001). The percentage with a minimum of 14 correct answers to the 15 questions increased from 18 to 63%(p<0.001). Adequate breast health practices were generally low but increased significantly with increasing ageand attendance at a previous lecture on breast cancer. Breast health practices were also higher among marriedwomen and housewives, and significantly associated with older age and greater breast health knowledge (p<0.001). Conclusions: Group educational lectures appeared effective for improving breast health knowledge amongJordanian women. However, even with the noticeable level of knowledge at the baseline, there were low breasthealth practices among the study participants. This necessitates further in-depth research to explore womensexperiences and socio-cultural barriers to breast health seeking behaviour in Jordan.