Introduction: Breast cancer is the most common cancer among women in the world and in our country. Despite early diagnosis and improved treatment possibilities, breast cancer is difficult to accept and a major source of anxiety. It brings various psychosocial problems to the agenda. In this study, we aimed to evaluate the effect of depression and anxiety in the patients admitted to the outpatient clinic with the complaint of a mass in the breast and to determine the effect of mass on the mental health of women. Methods: This study is an analytical case-control study. All of the participants were female (n=200). Patients filled the questionnaire containing the Beck Depression Inventory (BDI), the Beck Anxiety Inventory (BAI) and the sociodemographic data form. Results: There was no statistically significant difference between the case and control groups in terms of the marital status, living with someone, monthly income level, place of residence, occupation, and education level (p>0.05). There was a statistically significant difference between case and control groups in terms of the mean BDI score (19.6±1.05, 8.92±0.62, respectively, p<0.001). There was also a statistically significant difference between the two groups in terms of the mean BAI score (20.34±1.23, 7.88±0.71, respectively, p<0.001). Conclusion: In our study, the incidence of depression and severe anxiety was significantly higher in the women admitted to the outpatient clinic with the complaint of a breast mass than in the healthy women.