CYP1A1 enzyme is integral to the biotransformation of polycyclic aromatic hydrocarbons to carcinogenic compounds. This study aimed to screen mutations in exon 7 (ex7) of CYP1A1 and investigate its clinicopathological correlations in fresh tissue samples from 85 patients (42 women; 43 men) with colorectal carcinoma (CRC). Tumour tissues and matched non-neoplastic mucosa tissues were collected prospectively. Genomic DNA was extracted from all tissues, and subject to high-resolution melt curve analysis for CYP1A1-ex7. Sanger sequencing was employed to detect specific mutations. Three known single nucleotide polymorphisms (SNPs) were identified in both tumour and matched non-neoplastic tissue for the same individual. Of the 85 patients, one third (n = 28) harboured either rs1048943, rs1799814, or rs41279188. Patients who had a SNP at ex7 of CYP1A1 were significantly more likely to be over 65 years of age (p = 0.015). Furthermore, individuals harbouring a SNP at exon7 showed a low incidence of perineural cancer infiltration (p = 0.025) when compared to the wild-type population. Overall, polymorphisms at exon 7 of CYP1A1 are present in patients with CRC and associated with a few clinicopathological characteristics.