The presentation focuses on the development of students' mathematical literacy in Germany from the 9th to 10th grade. The study has been conducted within the Programme for International Student Assessment (PISA 2003) and investigates in a longitudinal design students' literacy in Germany in the 9th and 10th grade. The representative sample consists of 275 school classes with a total of 6020 students in Germany who took part in both tests. The test for Mathematical Literacy was based on the international framework in PISA. The aim of the research was to describe the development of mathematical competencies from the 9th to 10th grade on (a) an individual level, (b) a class level and (c) a school level. For the analysis, the data was scaled by using IRT methods. The competency scale was anchored at the international PISA 2003 scale in mathematics. The results show that the average gain in Mathematical Literacy on the individual level was 25 points on the competency scale (d = .33). However, only 60 percent of the students were able to substantially improve their competencies. On the aggregated level, the proportion of classes and schools that raised their average mathematical competencies was higher when compared to the individual level(school level: 97 percent, class level: 89 percent). Consequences of the results will be discussed.