The huge economic and social impact of high-tech industries on the fortunes of nation states has been widely recognised in recent years. Therefore, government policies encouraging the creation of new technology-based firms have become a priority in virtually all advanced economies. One factor underpinning the performance and growth of high-tech start-ups is presumably international activity of such firms. This study addresses the issues concerning the critical decision to internationalise. The findings confirm the extent and importance of internationalisation to young high-tech firms in the UK and Germany. Thus, if governments or venture capitalists are interested in the promotion of successful new technology-based firms they must, per force, be also interested in encouraging the processes of internationalisation.