The aim of this study is to examine the purpose of conducting the measurement and assessment practice of 4th and 5th grade teachers within the context of 2005 Primary School Mathematics Curriculum. To this aim, online questionnaire was administered to 512 fourth and fifth grade teachers who were randomly selected from 7 geographical regions and 15 cities in Turkey. Additionally, a case study was conducted with eight of them selected from Trabzon through interviews, observations and using document analysis methods. The collected data were analyzed using SPSS 15.0 and NVivo 8.0 programmes. The findings obtained from the questionnaire showed that elementary teachers conduct in a stable manner with the formative and summative assessment practice. However, findings obtained from case study revealed that there are some inconsistencies between the statements and classroom applications of elementary teachers, and that diagnostic and formative assessment practice, which were prescribed in 2005 mathematics curriculum, are not effectually conducted by them.