It has been recently reported that boron affects bone metabolism in humans and animals. In this study we examined whether boron affects the proliferation on various cell types, MG-63, HOS, Raw 264.7 and SK-N-SH. When treated with different concentrations of boron $(1,;10,;100{mu}M)$ for 24 and 48 hr, the proliferation of MG-63 cells was enhanced at $10{mu}M;(p<0.05)$, for 24 hr. In HOS cells, boron had no effect on cell proliferation at 24 or 48 hr. In addition, treatment of pre-osteoclastic cells (Raw 264.7) with 1, 10, $100{mu}M$ boron resulted in no effect on cell proliferation. Proliferation of neuronal cells (SK-N-SH) was enhanced by boron in a concentration dependent manner at low concentrations (0.1, 0.5, $1{mu}M$). Besides proliferation activity, boron has an effect on the enhancement of NO production in SK-N-SH cells in a concentration-dependent manner. These studies showed that boron enhances proliferation of osteoblastic cells (especially MG-63), depending upon the concentration of boron. These results also provide further evidence of the positive effects of boron in neuronal disease.