In the present study, Cordyceps sinensis extract (CSE) was evaluated to determine if it could protect pancreatic ${eta}$ cells against cytokine-induced cytotoxicity of RINm5F cells. Treatment of cells with cytokines resulted in a decrease of viability, which was caused by increase of nitric oxide (NO) production. CSE protected cytokine-mediated viability reduction in a concentration-dependent manner. Incubation with CSE also induced a significant suppression of cytokine-induced inducible nitric oxide synthase (iNOS) protein and NO production. The molecular mechanism by which CSE inhibited iNOS protein expression appeared to involve the inhibition of $NF-{kappa}B$ activation. The cytokine-stimulated RIN cells showed increases in $NF-{kappa}B$ binding activity compared to unstimulated cells. However, pretreatment with CSE inhibited cytokines-induced $NF-{kappa}B$ activation in RINm5F cells.