Objectives : To evaluate whether a relation between blood lead and zinc proto porphyrin(ZPP) was modified by gender in Korean lead workers. Methods : A cross-sectional study was conducted with 1,304 male and 101 female subjects in 1997. The relation between blood lead and ZPP were evaluated with linear, exponential, and quadratic models. Then, the different effect of gender on the relation was examined by adding the interaction terms in the each model. Results : $Mean{pm}SD$ of blood lead and ZPP level was different between male$(27.7{pm}10{mu}g/dl;and;51.3{pm}23.4{mu}g/dl)$ and female subjects$(22.5{pm}9.2{mu}g/dl;and;78.7{pm}38.6{mu}g/dl)$. After adjusting for possible confounders, the effect modification by gender was significant in linear$(eta=1.119,;p<0.001)$, exponential$(eta=Exp(0.008),;p<0.05)$, and quadratic model$(eta=1.388,;p<0.001)$. In separate analysis, a quadratic relation between blood lead and ZPP was shown in male lead workers$(eta=0.036,;p<0.001)$, but an exponential relation in female lead workers$(eta=Exp(0.029), p<0.001)$. Conclusion : Our data showed that the increasing rate of ZPP in female were always higher than in male lead workers, suggesting that females were more susceptible to occupational lead exposure than males.