This paper describes the multilingual text editor MtScript developed in the framework of the MULTEXT project.MtScript enables the use of many differentwriting systems in the same document (Latin, Arabic,Cyrillic, Hebrew, Chinese, Japanese, etc.). Editingfunctions enable the insertion or deletion of textzones even if they have opposite writing directions.In addition, the languages in the text can be marked,customized keyboard input rules can be associated witheach language and different character coding systems(one or two bytes) can be combined. MtScript isbased on a portable environment (Tcl/Tk). MtScript.1.1version has been developed underUnix/X-Windows (Solaris, Linux systems) and otherversions are planned to be ported to the Windows andMacintosh environments. The current 1.1 versionpresents several limits that will be fixed in futureversions, such as the justification of bi-directionaltexts, printing support, and text import/exportsupport. Future versions will use SGML and TEI norms,which offer ways of encoding multilingual texts andare to a large extent meant for interchange.