Up to recently, the processing of a decision problem via several Multiple Criteria Decision Aiding (MCDA) programs required to write the data in various formats. This chapter presents XMCDA, an initiative of the Decision Deck Consortium, which is a standard data model enabling to encode classical concepts from MCDA in XML. Among other things, it eases the analysis of a problem instance by various MCDA techniques compatible with XMCDA without requiring data conversions and it simplifies the sequencing of MCDA algorithms for the resolution of complex decision problems.