Arylamine N-acetyltransferase 2 (NAT2) is involved in both the detoxification and bioactivation of carcinogenic arylamines and other mutagens. This enzyme is polymorphic, and the fast acetylator phenotype is thought to be a risk factor for colorectal cancer. Here, we report on a study of colorectal cancer, with particular attention to meat intake and tobacco smoking, known risk factors for colorectal carcinomas, and polymorphisms of NAT2. The study was conducted on 35 colorectal cancer patients, 15 of their close family relatives and 10 controls. All patients underwent complete colonoscopy. DNA was extracted from blood to examine genetic variants of NAT2 using real-time polymerase chain reaction and fast, intermediate, or slow phenotype was detected from the genotype. Neither meat intake nor smoking was proved to be independently associated with colorectal cancer. Fast acetylator phenotype was not independently associated with colorectal cancer; however there was a statistically significant difference (P=<0.001) in percent distribution of the NAT2 4 allele between the patients, their relatives and the control groups.