WebLIS is a CDS/ISIS based Library Integrated System for WWW environment that is distributed free-of-charge by UNESCO since mid of the year 2004. The original language version of the WebLIS system is English and therefore its users from not English speaking countries will need to prepare own language versions of the system. This process is not as easy as preparing a new language versions of CDS/ISIS itself, because WebLIS does not use separate system databases with language dependant texts.

The paper describes various categories of user interface files of the WebLIS system (static HTML files, system definition files, HTML output templates, formats generating output data from various databases as well as formats and tables used for input data validation) and modification of these files required for WebLIS internationalization. Detailed instructions were provided on preparation of a single language version of the WebLIS system where another language replaces English as well as on preparation of a multilingual version of WebLIS.