Recently more and more attention has been paid to copyright protection in Lithuania. As a result, quite a number of governmental institutions have faced a problem. Most of them use unlicensed software. The alternative way to legalize software is to use free of charge (open-coded) software. That is why the Lithuanian Ministry of Education encourages educational institutions to use stable open-coded localized programmes; Open Office Pack falls into this category. At the moment Microsoft Office Pack dominates the software market. Open Office is a direct competitor of Microsoft Office, because it is free of charge. In the course if writing this paper, we got acquainted with different office programme packs. The potential and compatibility of Microsoft Office and Open Office packs with each other as well as with various operating systems have been described. Also, some experimental research has been carried out. We aimed to find out the differences of acquiring theoretical knowledge and practical skills while working with each of the packs. 9 and 10th formers participated in the experimental research. They were introduced to the basics of working with the Microsoft Office Word, Open Office Writer, Open Office Calc and Microsoft Office Excel programmes. In the course of the experiment, the level of pupils’ theoretical knowledge before and after the teaching and practice stages was measured. Also, their acquired practical skills were assessed. We have also questioned 38 IT teachers... [to full text]