Developments in the field of internet bring along the developments in education. The increase in the importance of the use of computers and the internet in the field of education necessitated the measurement of this dimension in the tests which are applied in wide scales. The research problem consists of the effect of the computer access and aim of computer use of 15 year-old students who participated in the computer part of the Programme for International Student Assessment (PISA 2006) over their achievements in science. The variant that best processes the student's achievement in science and the most important factor t hat affects achievement is student's access to computers.