The massive introduction of computers in educational settings has until now not resulted in the anticipated substantial increase in the quality and the outcomes of schooling in general, and of mathematics education in particular. This disappointing state-of-the-art is largely due to the educationally inappropriate use of the computer in learning environments, namely as an add-on to an unchanged classroom setting that contributes to preserving the status quo in mathematics education. Moreover, current applications including intelligent tutoring systems, are largely based on an inadequate conception of learning as a rather passive process of information absorption and knowledge accumulation. Against this background an emerging and research-based new view of the use of educational computing in mathematics is proposed. The basic idea of this expanding and innovative conception is that the New Information Technologies should be embedded in powerful collaborative learning environments as tools and resources that elicit and support in students active processes of knowledge acquisition, sense making, meaning construction, and problem-solving. Two recent examples of computer applications are briefly presented, and for one of them some already available research findings are reviewed. A short look into the future concludes the article.