We study the stability of endemic equilibriums of the deterministic and stochastic SIS epidemic models with vaccination.The deterministic SIS epidemic model with vaccination was proposed by Li and Ma(2004),for which some sufficient conditions for the global stability of the endemic equilibrium were given in some earlier works.In this paper,we first prove by Lyapunov function method that the endemic equilibrium of the deterministic model is global-ly asymptotically stable whenever the basic reproduction number is larger than one.For the stochastic version,we obtain some sufficient conditions for the global stability of the endemic equilibrium by constructing a class of different Lyapunov functions.