1588 Background: Excess of risk of several second primary malignancies after treatment for breast cancer (BC) has been reported. This risk can be related with shared risk factors, cancer susceptibility genes or prior treatments received. Hormonal factors and hormone therapy are known to be risk factors for both BC and some gynecological malignancies. The aim of this study was to asses gynecological cancer risk as a second neoplasm among BC patients in our population. Methods: Patients diagnosed with invasive BC (CIE10: C50.0-C50.9) and registered in the Girona Cancer Registry from 1980 to 2006 were included in our study. We analyzed their incidence of second gynaecological malignancies except for contralateral BC. Standardized Incidence Ratios (SIR) and absolute excess of risk (AER) of these patients compared to general population were calculated. Results: 6.209 patients were diagnosed of invasive BC in this period, with median age at diagnosis 62 years, median follow-up 4 years. 84 of them developed a second malignancy of gynaecological origin (SIR 1,98 CI 95% 1,59-2,44; AER 104,01/100.000 person-year). We observed 4 uterine cervix (SIR 0.64 IC95% 0,20-1,54), 3 vulvar-vaginal (SIR 0,96 IC95% 0,24-2,60), 13 ovarian (SIR 1,13 IC95% 0,63-1,89) and 63 uterine corpus neoplasms (UC), as well as 1 genital female tract neoplasm unspecified. High and statistically significant SIR was observed for gynecological malignancies in general and specifically for UC(SIR 3.14 IC 95% 2,44-4,00). With this finding, histology of UC cases was reviewed. 12 out of 63 were malignant histologies, not otherwise specified. Among the remaining 51, there were 8 type II (1 clear cell and 7 serous adenocarcinoma, 15.7%), 34 type I (endometrioid adenocarcinoma, 66.7%) and 6 carcinosarcomas (11.8%). There were also 2 adenosarcomas (3.9%) and 1 mucinous adenocarcinoma (1.9%). Conclusions: Women with previous BC have an elevated risk of developing a second primary gynecological malignancy compared with general population, particularly for UC. These patients should be followed up for its early detection. We detected a slight increase in unfavourable uterine carcinoma histologies respect to the general population. Further investigation of this finding is warranted.