Abstract Worldwide, hepatocellular carcinoma (HCC) is the fifth most common cancer and the second-leading cause of cancer-related death worldwide. In the U.S., the incidence rate of HCC has tripled since 1975. Although preliminary evidence suggesting a biological impact of diet on multiple inflammatory pathways implicated in hepatocarcinogenesis, the most comprehensive review by the WCRF/AICR concluded that the relationship between diet and HCC remains largely unknown. HCC is an inflammation-related cancer but few studies have investigated diet quality based on its inflammatory potential in relation to HCC risk. The empirical dietary inflammatory pattern scores (EDIP) score were calculated from validated food frequency questionnaires. It characterized dietary inflammatory potential based on circulating levels of inflammatory bio-markers. We prospectively followed 49,674 men in the Health Professionals Follow-up Study (1986-2012), and 74,139 women in the Nurses' Health Study (1984-2012). Cox regression analyses were used to calculate hazards ratios (HR) for HCC risk adjusting for body mass index, smoking, history of diabetes, race, physical activity, and regular aspirin use. We documented a total of 89 incident HCC cases (44 in women and 45 in men) over 28 years, encompassing 1,522,972 person-years of follow-up. Compared to the lowest tertile, the highest tertile of the EDIP score was associated with a multivariable HR for HCC of 2.86 (95%CI, 1.20-6.81) among women (P-trend=0.01) and of 0.68 (95%CI, 0.31-1.50) among men (P-trend=0.35). Future study is warranted to confirm this finding and elucidate the potential biological basis. Key words: inflammation, dietary patterns, HCC A. T. C. and X. Z contributed equally to this work. Citation Format: Yanan Ma, Tracey G. Simon, Fred K Tabung, Lindsay Y. King, Dawn Q. Chong, Long Nguyen, Trang VoPham, Charles S. Fuchs, Jeffrey A. Meyerhardt, Kathleen E. Corey, Hamed Khalili, Stephanie Smith-Warner, Raymond T. Chung, Edward L. Giovannucci, Andrew T. Chan, Xuehong Zhang. A prospective study of inflammatory diet potential and risk of hepatocellular carcinoma (HCC) abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5256.