Context: Endometrial polyps are a common gynecological disorder with malignancy risk between 0.2 and 12.9%. It is known that higher risk of polyp malignization is associated with Abnormal Uterine Bleeding (AUB) and higher age. Although the use of tamoxifen can be related to endometrial cancer by some studies, its role in the carcinogenesis is uncertain. Objectives: To analyze the use of tamoxifen as a malignancy risk factor in women with endometrial polyp. Methods: Retrospective study including 597 women submitted to polypectomy hysteroscopic between 2010 and 2015 in a tertiary academic hospital (CAISM - University of Campinas). Women were divided in two groups: exposed to tamoxifen use (n=104) and not exposed to the drug (n=493). The primary outcome was the prevalence of endometrial cancer. The dependent variables were: age, parity, number of years after menopause, presence of AUB, endometrial pattern according to hysteroscopy, endometrial thickness. Statistical tests were: Mann-Whitney and Chi-square test for continuous and categorical variables, respectively. Multivariable analysis was performed using the Poisson regression. Patients: We analyzed the clinical charts of 597 women treated for endometrial polyps in our hospital. 104 in use of tamoxifen, 493 not exposed to the drug. Intervention: None. Main Outcome Measure: The presence of endometrial cancer in anatomopathological exam. Results: There were 4 cases of endometrial cancer among the tamoxifen group (3.85%) against 39 on the other group (7.91%) (p=0.145). After multivariate analysis, women that were not exposed to tamoxifen were at an increased risk of malignancy when they presented AUB (RR=4.1; CI 95% [2.05-8.12];p <.001), were nulliparous (RR=2.99; CI 95% [1.47- 6.08] p=0,002) and displayed at Transvaginal Ultrasound endometrial thickness>12.15mm (RR=2.4; CI 95% [1.24-4.70] p=0,009). On the tamoxifen group, women were at risk for malignancy when they presented AUB (RR=34.7; CI 95% [3.5-323.67] p < 0,001) Conclusion: The use of tamoxifen was not related to a higher risk of endometrial cancer within women with endometrial polyp. AUB was a symptom presented in both groups and presented a higher association with malignancy.