To further understand the significance of bone as a target tissues of lead toxicity, as well as a reservoir of systemic lead, it is necessary to define the effect of lead on the calcium release activated calcium influx (CRACI) in primary cultures of human osteoblast-like cells (OLC). $Pb^{2+}$ inhibited the immediate CRACI dose-dependent manner. Influx of $Pb^{2+}$ into human OLC was increased dose-dependent manner. The present study demonstrates that the interference of $Pb^{2+}$ with CRACI of human OLC is at least twofold: (1) the initiation of CRACI, i.e., the measurable influx of $Ca^{2+}$ upon $Ca^{2+}$ readdition, is partially inhibited by $Pb^{2+}$ and (2) the influx of $Pb^{2+}$ was enhanced after CRACI had been induced.