In this study, the inhibitory effects of selenium-containing heterocyclic compound, selenazol derivatives on LPS-induced nitric oxide production in macrophage cells (RAW 264.7) were assessed. Five kinds of selenazol derivatives were shown to exhibit $5.4{sim}41.7%$ of inhibitory effects at $10{mu}M$. Among them, 2-(4-chlorophenyl)-1,3-selenazol-4-one generally evidenced a high degree of inhibitory activity with $IC_{50}=11.8{mu}M$, and this compound also profoundly suppressed iNOS expression in LPS-treated RAW 264.7 cells. These results indicated that 2-(4-chlorophenyl)-1,3-selenazol-4-one might function as an anti-inflammatory agent via the inhibition of iNOS-mediated nitric oxide production.