Introduction: Breast cancer is the most frequent tumor among women in Poland, accounting for about 20% of malignant tumor cases within this population and causing about 15% of all deaths. Annually, there are 11000 cases of breast tumor in Poland, with about 5000 deaths among Polish women. The primary and secondary tumor prevention prophylaxis might change this unfavorable situation as far as the death rate and the increasing number of malignant tumor cases is concerned. One way, among others, to detect breast cancer is self-examination. The aim of the current work was to examine the influence of self-examination on breast cancer detection in women after surgery. Material and methods: The research was conducted in the Breast Cancer Ward at Oncology Center in Bydgoszcz, from October 2004 to February 2005. The research was conducted on 100 randomly chosen women, who had undergone tumor surgery, aged from 28 to 77 years old (average 55,24). The research was performed using diagnostic survey method and medical records review. Results: The study group comprised mostly of women with higher education, inhabitants of cities, retired or receiving disability pension. A vast majority of the surveyed women had had two deliveries and their children had been breastfed. Almost all of the study group participants used to have periodic gynecological examinations, however, most of them did not undergo breast examination performed by a gynecologist. They obtained the knowledge about self-examination from TV, as such information was provided by gynecologists very seldom. Most women had performed breast self-examination once a month. Mammography was done in above half of them. 72% of women detected small breast tumor themselves. Conclusion: Self-examination in women after surgery has had a significant influence on tumor detection. It has also been discovered that neither the size of breasts nor the frequency of self-examination are of significance in tumor detection.