Abstract The 5-year survival rate for breast cancer has increased from 78% during 1993 to 1995 to 90% during 2004 to 2008 among Korean women. Despite such improvement, breast cancer remains the leading cause of cancer mortality among women. One-carbon metabolism, which requires adequate supply of methyl group donors and B-vitamins, may affect breast cancer prognosis. This study aimed to investigate the associations of dietary intake of vitamin B2, vitamin B6 and folate before diagnosis and breast cancer prognosis. We assessed dietary intake from Food Frequency Questionnaire in 980 women who were newly diagnosed and histopathologically confirmed first primary breast cancer from hospitals located in Seoul, Korea in 2004 to2007 and followed for an average of 5.3 years. Univariate and multivariate analyses were used to investigate association between dietary intake of B-vitamins and disease free survival. There was no association between dietary intake of B vitamins and breast cancer prognosis. However, we found higher dietary intake of vitamin B6 was associated with improved survival in patients with BMI more than 25kg/m2 (harzard ratio (HR), 0.32; 95% confidence intervals (CI), 0.11-0.94) or positive hormone status in estrogen receptor(ER)/progesterone receptor(PR) (HR, 0.39; 95%CI, 0.16-0.97). Our study suggests that the high intake of vitamin B6 is associated with improved breast cancer survival in patients with higher BMI and positive hormone status in ER/PR. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 641. doi:1538-7445.AM2012-641