Abstract Background: Cigarette smoking, high intake of alcohol, and lack of physical activity are associated with increased colorectal cancer (CRC) risk, but little research has been conducted to investigate the association between these modifiable lifestyle factors and survival after CRC diagnosis. Methods: Therefore, we prospectively assessed the association between smoking status and intensity, baseline alcohol intake, lifetime pattern of alcohol intake, physical activity and all-cause and CRC-specific death among 3,916 participants diagnosed with colorectal cancer (colon = 2,454, rectum = 1,462) between 1992 and 2008 in the EPIC cohort. Multivariable Cox proportional hazards models were used to calculate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs). Results: There were 1,303 deaths, 1,039 (80%) due to CRC. Mean follow-up after CRC diagnosis was 4 years. In multivariable analysis, current vs. never smokers had an increased risk of all-cause death (HR = 1.22, 95% CI: 1.04-1.44). Greater intensity of smoking (26+ cigarettes per day) was associated with almost a doubling in the risk of all-cause death when compared with never smokers (HR = 1.75, 95% CI: 1.12-2.73). Alcohol consumption was not statistically significantly associated with survival (HR = 1.00, 95% CI: 0.98-1.02 per 6 g per day), however former heavy drinkers had an increased risk of all-cause death (HR = 2.68, 95% CI: 1.13-6.39). Total physical activity was not statistically significantly associated with CRC survival. Additional subgroup analyses were conducted by sex, age at diagnosis, cancer stage and grade, location of tumor, time between blood collection and cancer diagnosis, year of diagnosis, follow-up period, and body mass index. Results for CRC-specific death were similar to those reported for all-cause death. Conclusions: Our preliminary results suggest that cigarette smoking and being a former heavy drinker before cancer diagnosis are associated with worse survival among Western European patients with CRC, but further research is needed to confirm these results. Citation Format: Veronika Fedirko, Elio Riboli, Teresa Norat, Anne Tjønneland, Mazda Jenab, on behalf of the EPIC CRC Working Group. Prediagnostic smoking, alcohol intake, physical activity and survival after colorectal cancer diagnosis in Western European populations. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2922. doi:10.1158/1538-7445.AM2014-2922