Background: Breast self examination (BSE), performed regularly every month, is one of the most important methods in the early diagnosis of breast cancer. This study was performed with the aim of establishing the knowledge, attitudes, and behavior of women working in government hospitals within the province of Samsun regarding BSE. Materials and Methods: This cross-sectional study was conducted between January-March 2012, on a total of 550 women (500 health personnel, and 50 general administration services (GAS) workers) from 7 government hospitals and the Cancer Early Diagnosis, Screening, and Education Centre (CEDSEC). Percentages were used for the descriptive statistics, and the chi-square test for the evaluation of statistical importance. Values of p<0.05 were accepted as significant. Results: The mean age of the participants was 36.2± 15.3, and 42.5% were in the 30-39 year old age group, 78.0% being married. Seventy-eight point four percent (78.4%) of the health personnel and 76.0% of the GAS workers performed BSE. However, the rates of performing BSE regularly every month were only 25.6% and 5.0%. Within the health personnel, 1.4% stated that they did not perform BSE because they found it unnecessary as they had no history of breast cancer in their family, 3.6% did not do so due to fear and stress, 13.2% because they forgot, and 14.6% because they had no complaints. Some 22.2% of the health personnel and 52.0% of the GAS workers had undergone mammographic evaluation, the difference being significant (p<0.05), 84.1% of the health personnel and 61.9% of the GAS workers knowing symptoms of breast cancer. Conclusions: Women in society should be brought to a certain level of awareness and knowledge regarding BSE. It is of the utmost importance that health personnel, who carry the responsibility for counseling and enlightening society, should interiorize the necessary knowledge, attitudes and behavior.