Abstract: The text incorporates long-term defaultable corporate bonds and credit risk in a dynamic stochastic general equilibrium business cycle model. Credit risk amplifies aggregate technology shocks. The debt-capital ratio is a new state variable and its endogenous movements provide a propagation mechanism. The model can match the persistence and volatility of output growth as well as the mean equity premium and the mean risk-free rate as in the data. The model implied credit spreads are countercyclical and forecast future economic activities because they affect firm investment through Tobin's Q. They also forecast future stock returns through changes in the market price of risk. Finally, The model shows that financial shocks to the credit markets are transmitted to the real economy through Tobin's Q.