This paper develops a Bayesian approach to estimating exchange rate target zone models and rational expectations models in general. It also introduces a simultaneous-equation target zone model that incorporates stochastic realignment risk. Using FF/DM and IL/DM exchange rate data, we find that the signing of the 1987 Basle-Nyborg Agreement reduces both the magnitude and the likelihood of a central parity realignment, while the lagged exchange rate deviation from its central parity increases them. Furthermore, the interest rate policies and the monetary conditions of the participating countries signal a forthcoming realignment. In general, we are unable to improve upon a simple random walk model in out-of-sample exchange rate prediction by introducing target zone models.