Bowel habit has been associated with colorectal carcinogenesis; however, findings from epidemiologic studies have been limited and inconsistent. The aim of this study was to explore the association between bowel habit and colorectal cancer (CRC) risk in the UK-Norfolk arm of the European Prospective Investigation Into Cancer and Nutrition (EPIC-Norfolk), a study of 25,663 men and women aged 45-79 years at entry. Having loose stools compared to soft stools was associated with an approximately 3-fold increased risk, and the association remained significant when lifestyle factors and bowel habit variables were included as covariates in the model (odds ratio (OR), 2.80; 95% confidence interval (CI), 1.41-5.56). The significantly elevated risk estimate persisted when we further excluded CRC cases within 3 years of follow-up. Frequency of bowel movement, stool quantity, feeling discomfort and laxative use was not overall associated with CRC risk. These findings suggest that having loose stools may be an indicator of colorectal cancer risk.