The paper deals with the facts obtained from TIMSS 2003 (Trends in International Mathematics and Science Study). This international comparative study, which includes 47 participant countries worldwide, explores dependence between eighth grade students' achievement in the areas of mathematics, physics, chemistry, biology and geography, and basic characteristics of context for teaching and learning in school and at home. In the sense, different options of using modern technology equipment and its influence to students' achievement are explored in the TIMSS 2003 assessment. The main topic of the paper is using computers and calculators in teaching and its implications to students' overall achievement at the end of primary school education. The TIMSS 2003 international overall results in this area show that using computers in teaching doesn't significantly contribute to better students' achievement in the field of mathematics and also show some level of significant influence on students' achievement in the field of science. Moreover, the results show that using calculators in mathematics teaching improve overall students' achievement. Connectedness between using computers/calculators and students' achievement is especially explored and presented in the frame of students' sample in four countries, the United States, the Netherlands, Bulgaria and Serbia. (Contains 12 tables.) [This article is a result of the project "Education for Knowledge-Based Society" No. 149001 (2006-2010), financially supported by the Ministry for Science and Environmental Protection, Republic of Serbia. This article was also published in: The Fourth International Conference on Informatics, Educational Technology and New Media in Education: Proceedings (253-263). Sombor (Serbia): Faculty of Education.]