This paper develops a dynamic stochastic general equilibrium model, which is calibrated for the Peruvian economy and can be useful for the design and analysis of monetary policy. The model includes a second currency that replaces partially the domestic currency in its functions of unit of account, medium of payment and reserve of value; phenomenon known in the economic literature as partial dollarization. We also include certain real, nominal and financial rigidities to replicate the empirical regularities of the Peruvian macroeconomic data. The model reproduces relatively well the main stylized facts of the Peruvian economy. Moreover, we show how dollarization reduces the power of monetary policy to affect output and increase the vulnerability of the economic activity to foreign shocks. Furthermore, we perform some exercises that show the importance of credibility in the actions of the monetary authority to anchor expectations and to reduce deviation in the inflation rate.