Abstract Background: As survival increases in patients with breast cancer (BC), long-term care is required. Studies have shown that the psychosocial situation of this patients changes according to age and the types of treatment they received. Quality of life (QoL), unmet needs (UN), and social support (SS) have been significantly related to the way they live their survivorship. However, it is still unclear how these variables are affected by adjuvant endocrine therapy (AET) in Mexican patients with BC, to address and provide appropriate interventions. Objective: To describe the level of quality of life, unmet needs and social support, and to evaluate their relationship with the type of AET. Method: 200 patients with BC under AET were enrolled in a cross-sectional and correlational design. We administered QoL (EORTC-30 and BR-23), UN (SCNS-SF32), SS (MOS-SSS14), validated and standardized instruments in Mexican population. Premenopausal patients with ovarian function suppression were excluded. Non-parametric analyzes of U Mann Whitney and Spearman's correlation were used. Results: Mean age of the 186 patients evaluated was 54.52 (SD=10.65) years. Most of patients had elementary school (32.8%), were married (49.5%), housewives (60.2%), and catholics (86%). 54.8% underwent tamoxifen, 25.8% exemestane, 12.9% letrozol, 6.5% anastrozol. Mean time of AET were 2.59 years and 3.53 years since diagnosis. They reported a good level of global QoL (mean= 80 points, 0-100); however, they experienced insomnia (25.44 points), financial difficulties (24.19), fatigue (23.77), constipation (21.68) and pain (18.54); besides, adequate body image perception (91.6 points). The most UN were on information and the health system 31.13 (0-100 score), sexual (29.23) and psychological (28.21). The most frequent SS type was affection (88.46 points) and emotional-informational (79.56 points). Patients under anastrozole in comparison with exemestane, tamoxifen and letrozol reported significantly more nausea-vomiting (p=0.028; p=0.041; p=0.002 respectively), insomnia (p=0.008; p=.014; p=0.032, respectively), and appetite loss (p=0.049; p=0.049; p=0.04, respectively). We found that patients with anastrozol perceived significantly less SS than other types of AET (p=<0.005). It highlights that patients who received letrozol perceived significantly better future perspective (QoL). Our data also shows that the higher QoL level and the fewer reported symptoms the lower the UN. Conclusions: These results are consistent with previous studies in terms of information and psychological UN, and its relationship with QoL. Despite the small percent of patients treated with anastrozole in our study, they had more side effects than other aromatase inhibitors. In addition, it shows that postmenopausal survivors patients with BC still have sexual UN. This study is the first on Mexico exploring differences in perception of QoL, UN and SS according AET type. We concluded that the health care professionals who attend postmenopausal survivors patients with BC in the real clinical practice, should be aware of that long-term intervention includes care to sexual and psychological UN in the same importance as to the adverse events of treatment. Citation Format: Gálvez-Hernández L, Páez-Gerardo I, Ramírez-Medina R, Neri-Flores V, Bargallo-Rocha E, Villarreal-Garza C, Esparza N, Flores-Díaz D, Mohar A, Cabrera-Galeana P. Quality of life, unmet needs and social support of patients with breast cancer during adjuvant endocrine therapy in Mexico [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-12-15.