AIM: To estimate population attributable fractions for modifiable lifestyle factors and colorectal cancer in New Zealand. METHOD: Relative risks for lifestyle risk factors for colorectal cancer, and population data on the prevalence of exposure in New Zealand, were used to estimate the population attributable fraction (PAF) for each risk factor. RESULTS: Six modifiable lifestyle risk factors were identified. The PAFs for these risk factors were 9% for obesity, 7% for alcohol, 4% for physical inactivity, 3% for smoking, 5% for consumption of red meat and 3% for processed meat. PAFs di ered by ethnic group and sex. In women, the highest PAFs were 19% for obesity in Pacific women, 14% for obesity in Māori women, 7% for physical inactivity in Asian women, and 8% for obesity in European/other women. In men, the highest PAFs were 17% for obesity in Pacific men, 14% for high alcohol consumption in Māori men, 5% for physical inactivity in Asian men and 9% for high alcohol consumption in European/other men. CONCLUSION: If obesity, alcohol consumption, smoking and consumption of red and processed meats could be reduced, and physical activity could be increased among New Zealanders, it would reduce the risk of colorectal cancer considerably.