XmdvTool is a public-domain software package for the interactive visual exploration of multivariate data sets. It is available on all major platforms such as UNIX, LINUX, MAC and Windows. XmdvTool is developed using Qt and Eclipse CDT.XmdvTool also supports a variety of interaction modes and tools, including brushing in screen, data, and structure spaces, zooming, panning, and distortion techniques, and the masking and reordering of dimensions. Univariate display and graphical summarization, via tree-maps and modified Tukey box plots, are also supported. Finally, color themes and user customizable color assignments permit tailoring of the aesthetics to the users.