Background: Breast cancer in Iraq is the most dangerous disease which has the highest incidence that threats women lives in Iraq for the last twenty years. Objectives: To assess the knowledge level of women about breast cancer in relation to some socio-demographic and other relevant factors. Subjects and methods: A cross-sectional study included women attending Ibrahim Pasha and Ali Kamal Health Centers/Sulaimany City. Data were collected by self-administered and interviewing questionnaires from 1st October to 31th December 2012. Total number of the women was 802. The data were analyzed using SPSS version 19.0. Results: There was a significant association between the knowledge score of breast cancer risk factors and protective factors (P=0.001) with the age and level of education. There is a significant association between those with knowledge score of risk factors and protective factors of breast cancer and history of breast mass (P= 0.045, family history of breast mass (P= 0.042). There is a significant association between knowledge score of symptoms of breast cancer and age (P= 0.001) occupation (P= 0.0002), marital status (P= 0.041), those with use of hormonal replacement therapy (P= 0.016) and had history of breast infection (P= 0.031). Conclusion: Participants had an accepted knowledge about breast cancer. There was a significant association between the knowledge level of women about breast cancer in relation to some socio-demographic, and other relevant factors.