We illustrate the application of BUGS, a Bayesian computer program, with two examples. The algorithm used in the program is a popular Markov chain Monte Carlo procedure called Gibbs sampling. Bayesian analysis based on simulation has been applied to a wide range of complex problems (Gilks, Richardson, & Spiegelhalter, 1996). The availability of a general purpose program like BUGS should facilitate important applications of Bayesian inference in psychological research.