e11600 Background: Periodontal diseases arise from inflammatory diseases involving the periodontal connective tissue as a common factor. Estrogen produces inflammatory changes that worseness the periodontal preexistent status; and alters the microbiologic environment acting as a nutrient. The objective of this study is to determinate the relation between the treatment with tamoxifen and the prevalence of periodontal disease in women with breast cancer. Methods: Observational study. Sample: 70 postmenopausal patients, distributed in the following groups: Group 1 (N: 17) patients with breast cancer diagnosis and treated with tamoxifen less than one year; Group 2 (N: 18) patients with breast cancer and treated with tamoxifen for 1 to 2 years; Group 3 (N: 18) patients with breast cancer and treated with tamoxifen for 2 to 5 years; Group 4 (N:17) patients with breast cancer that have finalized their treatment with tamoxifen. A poll was performed between these patients, a periodontal scale and a mouth hispid was performed. Microbiologic standard tests were performed for Candida and also molecular biologic tests. Results: Group 1: health: 0%, severe periodontal diseases: 22% Group 2: health: 0% severe periodontal disease: 25% Group 3: health: 25% severe periodontal disease: 10% Group 4: health: 35% severe periodontal disease: 5%. Microbiologic cultives: presence of Candida albicans, tropicalis, parapsilosis, dubliniensis and glabrata. The maoyor variety of species were isolated from Group 1. Conclusions: The time frame with Tamoxifen treatment shows differences in the Periodontal status and reveals differences in the growth of Candida species because a decrease in number and species of yeast, this means an additional benefit in the studied population. We believe it is important to run this study with larger populations in order to determine the benefits of the treatment with Tamoxifen.