As the new millennium dawns, attention will focus on the fallout from Year 2000 (Y2K) computer problems. This paper describes a risk-based Y2K Decision Support System (DSS) that assesses the mission critical processes in an organisation's supply chain. A graphical user interface, data-mining and scenario-based contingency planning are key features. Problem formulation, model development, and limitations are described. A real organisation is used to illustrate the use of this decision support tool for Y2K risk assessment and reduction. A demonstration copy of the software is available on request.