Abstract: Causal mediation analysis is an exciting new area innovation in biostatistics. It concerns the analysis of causal pathways that link the exposure variable to the outcome. For example, when investigating the effect of obesity on mortality, we may be interested in the mediating role of high blood pressure. Does obesity affect mortality through pathways other than hypertension? In recent years there have been new developments in mediation analysis techniques using the framework of counterfactuals (potential outcomes). In this talk, I will give an overview of causal mediation analysis, and opportunities for Bayesian contributions to new methodology. I will illustrate mediation analysis in a study that examines the determinants of mortality among offenders with mental illness in British Columbia. This is joint work with Julian Somers and Scott Venners from the Faculty of Health Sciences @SFU.