Background:CC chemokine receptor 5 (CCR5) is introduced as an immune response modulator. The activity of CCR5 influences breast tumour development in a p53-dependent manner. This study aimed to investigate the frequency of CCR5delta32 and its association with the risk of breast cancer in 1038 blood samples in North East of Iran.Methods:In this case-control study, we genotyped 570 control samples and 468 breast cancer patients by a gel electrophoresis-based gap-polymerase chain reaction (gap-PCR) method Mashhad, Iran. The data were analyzed using the SPSS software.Results:Of 570 controls included, 542 (95.09%) had CCR5delta32 wild/wild (W/W) genotype, 28 samples (4.91%) had CCR5delta32 wild/deletion (W/D) genotype and none of them were CCR5delta32 deletion/deletion (D/D) genotype (0%). While 428 samples of patients (91.45%) had CCR5delta32 W/W genotype, 40 samples (8.55%) had CCR5delta32 W/D and CCR5delta32 D/D homozygous was nil (0%) amongst cases. All samples were in the Hardy–Weinberg equilibrium (P>0.05). According to the allele frequency, D allele, as a risky allele, in the cases was more than the control samples (0.0427 vs 0.0245, respectively) (P=0.0206). Hence, W/D genotype may confer a risk effect (OR=1.77, CI: 1.09–2.90; P=0.0206) compared with WW genotype between case and control groups.Conclusion:There is a statistically significant association between CCR5W/D and breast cancer risk. CCR5 may be regarded as a target for the prevention of breast cancer in certain conditions such as interaction with p53 variants, which remains to be further investigated.