The present study investigated the association between polymorphic variants of HSP1A genes (HSP70 gene family) and chronic mercury intoxication (CMI) development in 87 workers of caustic soda production plant, who have been chronically exposed to mercury vapor. The polymorphic loci HSPA1B (+1267A/G и +2074G/C) and HSP1AL (+2437T/C) were studied. Genotyping was performed using PCR-RFLP and logistic regression analysis was used for three genetic models for the investigation of the required associations. We found that frequency of genotype GG HSPA1B (+1267A/G) in group of patients with CMI (n = 45) was higher (p = 0.003) compared with the group of workers without the disease (n = 42). Recessive genetic model found a strong association of the homozygous GG genotype for rare allele with the development of CMI (OR = 13.26, p = 0.001). The obtained associations indicate that the HSPA1 could be important in mechanisms of CMI development and progression and help to develop the criteria for assessing individual's susceptibility to its development.