The purpose of this study is to investigate the levels of cognitive domains of Malaysian Mathematics primary four textbooks developed under the old and new curriculum based on Trends in International Mathematics and Science Study (TIMSS) 2015 Mathematics Framework. This study adopted content analysis where the mathematical tasks from the textbooks were classified in terms of type of tasks and cognitive domain. The results of the study showed that a large portion of mathematical tasks in the two textbooks are in the 'knowing' domain even though improvements have been made in the new version of mathematics primary four textbook which has more mathematical tasks in 'applying' and 'reasoning' domain compared to the old textbook. The findings of the study suggest the structure of Malaysian textbook to be updated to the current world changes by increasing the tasks in applying and reasoning domain. However, the effort to reduce the gap between the intended curriculum and the supporting textbooks need to be carefully planned such that students of different abilities can benefit. Meanwhile practitioners have to be smart in selecting and providing extra supplementary resources to serve the need of their students.