The average achievement of Latvia’s students in mathematics PISA 2006 study in comparison with PISA 2003 study actually have not changes (the increase is only by 3 points, which is not statistically significant). The achievement of Latvia in the international comparison in 2006 is even lower (4 positions lower in the ranking, see Table). Mean achievement of Latvia’s students in mathematic literacy in PISA study PISA 2003: Score Point : Latvias mean: 483 / OECD average 500 Rank (Latvia) : 27 (21 – 28), below the OECD average PISA 2006 Score Point Score Point : Latvias mean: 486 / OECD average 498 Rank (Latvia) : 31 (26 – 32), below the OECD average The aim of the paper is to find the possible explanation for this situation, when studying the relationship between the new curriculum in mathematics in basic education of Latvia (Grades 1 – 9) and the content of PISA test. The research question is to define the correspondence (overlap) between the content of mathematics items of PISA test and mathematics curriculum of Latvia. First, the study will concern the content analysis of the mathematics items of the PISA test and the Standard of basic education in mathematics defining the adequacy of the test items to students in Latvia. The experienced teachers - mathematicians and other experts will be involved in the process of performing the content analysis. The results of Latvia’s students in PISA 2006 and PISA 2003 studies will be analyzed in the next stage in separate groups of mathematical items in which the degree of adequacy between the PISA test and Latvia’s curriculum differs. Finally, common conclusions will be drawn about the correspondence between Latvia’s mathematics curriculum and the PISA test. Stating the lack of correspondence between Latvia’s mathematics curriculum and the PISA test, which could be significant for the quality of mathematics education in Latvia, the recommendations will be provided for improving the content of mathematics curriculum for the basic school in Latvia.