Breast cancer BC is the most frequent cancer among women worldwide. Vitamin D inhibits cell proliferation through the vitamin D receptor (VDR), which may have an impact on the risk of BC. This studywas designed to association between VDR (Taq1 T/C)(rs 731236) single nucleotide polymorphism SNP with risk of BC in Iraqi women together with serum levels 25-hydroxyvitamin D [25-(OH) D] and CA 15-3. A case -control study women was carried out at Department of Biochemistry, College of Medicine, University of Baghdad, during the period from in the period from to October 2019 to January 2021. It included 95 women with period BC that had not received any chemotherapy. The phenotyping included the measurements of serum CA 15-3 and 25-(OH) D by using ELISA Kits. The genotyping analysis comprised of VDR- Taq1 (T/C) [rs731236] by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) analysis. The mean (±SD) value of serum CA15-3 and 25-(OH)D levels were significantly increase (p < 0.05), in BC women than in control. The risk of BC was significantly increased with VDR Taq 1 SNP (T/C) (rs 731236) in heterozygous and dominant genotypes in women with BC. The TC carriers (OR=1.904, 95% C.I= 1.055, 3.43, X2=4.612, p= 0.03) and dominant TC+CC (OR=1.895, 95%C.I=1.664, 3.37, X2 = 4.75, P= 0.02). Homozygous CC carriers (OR=1.798, 95%C.I = 0.382, 8.457, X2= 0.565, p= 0.45) did not observe significant difference, and border line allele frequency C allele carriers (OR=1.888, 95%C.I=0.941..3.789, X2=3.239, p= 0.07) when compared with wild TT genotype. The significant association between VDR Taq 1 SNP (T/C) (rs 731236) and plasma V D levels among BC women (p= 0.04). In Conclusion the VDR Taq 1 SNP (T/C) (rs 731236) variant could be regarded genetic risk factor for BC development. Vitamin D receptor gene-Taq1 polymorphism was associated with plasma VD.