Catalase0represents a critical enzyme in the organism's defense system against oxidative stress, a physiolog1qaical state implicated in the pathogenesis of various cancers. As a primary antioxidant defense enzyme, catalase plays a vital role in mitigating oxidative damage. Substantial evidence from numerous studies indicates that genetic polymorphisms in the CAT gene are significant in cancer etiology. This investigation aimed to elucidate the influence of the CAT gene polymorphism0(rs7943316)0on breast cancer susceptibility. Genomic DNA was isolated from blood samples of breast cancer patients and a control cohort. The specified0singlenucleotide0polymorphism (SNP) was analyzed using polymerase.chain reaction (PCR) coupled with restriction fragment0length.polymorphism (RFLP)0analysis. Genotype distribution in the control group was as follows: the heterozygous A/T genotype was most prevalent0(55 %), followed0by the homozygous T/T genotype (36.7%), while the homozygous A/A genotype was not0observed (8.3 %). In the breast cancer (BC) patient group, the A/T0genotype was also the most frequent (51.7%), followed by T/T (31.7%) and A/A (16.6%).Analysis revealed that individuals carrying the A/T and T/T genotypes exhibited an elevated odds ratio for breast cancer development (OR = 2.129, P = 0.209 and OR = 2.315, P = 0.183, respectively). However, these associations were not statistically significant. Furthermore, comparative allele frequency analysis showed no significant difference in the distribution of the0T.allele of the CAT gene (.rs7943316)0between the breast cancer0patients and the control group (P = 0.290). In conclusion, the findings of this study indicate that the development of breast cancer is not associated with polymorphisms of the CAT gene at the rs7943316 locus.