The goal of this study is to investigate if metallothionein (MT) gene polymorphism affects the susceptibility to lead as well as renal function parameters and blood pressures (BP) in workers exposed to lead for extended period of time. By means of real-time polymerase chain reaction, the MT4-216 A/G genotypes classified as rs396230 in the single nucleotide polymorphism database of the National Center for Biotechnology Information (database) were analyzed on 113 workers of a lead battery-recycling factory. Workers with G (mutant) allele were more susceptible to the toxic effects of lead on their systolic BP and serum renal function parameters. Their BP was 10 mmHg higher than those with wild-type (AA type) allele. Among subjects with the 3-genome, the GG mutant type subjects appear to be more susceptible to lead. Regression models of serum creatinine and BUN showed significant differences between the GG and GA types compared to AA type subjects. This cross-sectional study shows that workers with different MT-4 genotypes have different lead-induced adverse health effects. Those with the G allele have the greater susceptibility to lead so their exposure should be reduced.