Backgroud: Breast cancer is the most common malignant disease of woman of reproductive age. It is treated with surgery, chemotherapy, hormonal therapy and radiation. A diagnosis of breast cancer in young women poses a threat to fertility. A basic assessment of ovarian reserve can help in considering different fertility preservation options. Choosing appropriate strategy also depends on the age, type of chemotherapy, partner status and motivation of the patients. Aim:The aim of the research is to determine the fertility potential of oncology patients of reproductive age treated for breast cancer. Hypotheses:Chemotherapy and radiotherapy treatment for breast cancer reduces women's fertility. Methods:The research was conducted on a sample of 50 women of childbearing age who were found using the Hospital Information System based on diagnosis and age. The respondents were contacted by phone and a telephone survey was conducted with verbal consent. The survey with which the research was conducted contains questions related to diagnosis, reproductive history and laboratory determination of parameters of fertile potential. Within descriptive statistics, variables were analyzed using descriptive indicators of the distribution of real and relative frequencies, measures of central tendency - arithmetic mean, median, mode, quartiles and measures of dispersion (scattering) - standard deviation, variance and range. In the framework of inferential statistics, data were tested with the Student's t test for large independent samples, the Student's t test for large dependent causes, and the chi-square test. P values for static analysis will be two-sided, and the significance level will be α=0.05. Results: On the basis of the mentioned variable, it was shown that out of 50 test subjects, only 2 managed to have a birth/abortion after treatment, which already suggests a low probability of a possible birth/abortion after treatment. Arithmetic means of the number of births before and after treatment were also compared. It was shown that they are statistically significantly different at the 5% significance level. Conclusion: The subjects were not given any information about the possibility of creating a hormonal profile and none of them were informed about the meaning of anti-Mullerian hormone. The test subjects were not instructed at all to create a hormonal profile and anti-Millershormone.