The Third International Mathematics and Science Study (TIMSS) was conducted in more than 40 countries and lasted from 1990 to 1998. It included an extensive study of the content of curricula and textbooks and focused on Mathematics and Science achievement tests to Elementary School students in Grades 3 and 4, Secondary School students in Grades 7 and 8, as well as Grade 12. Specifically in Greece, the study was enriched with achievement tests administered to 9th Grade students during the following year from the data collection for Grades 7 and 8, as well as interviews with students in a limited number of school units. TIMSS also consisted of background questionnaires for students, Science and Mathematics teachers and for school principals. In the current documentation, data collected in Greece regarding students' attitudes towards Mathematics and Science in Grades 4 and 8 are presented.