Terminal-acetylated hyperbranched poly(ethylene glycol) derivatives containing diethylene and triethylene glycols and 3,5-dioxybenzoate branching units were prepared and the ionic conductivities of these polymers complexed with lithium metal salts such as LiCF3SO3 and Li(CF3SO2)(2)N as polymer electrolytes were investigated. It was found that the hyperbranched polymer with a triethylene glycol chain and with Li(CF3SO2)(2)N shows higher conductivity and also the number of charge carriers increases with Li(CF3SO2)(2)N salt concentration.