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This research was descriptive qualitative research. This study aims to analyze the errors of students in the problems of surface area and volume on the prism and pyramid then to expose causal factors. The subject of this research was 29 students 9th of SMP Negeri 40 Bandung, that was chosen by purposive sampling technique. Data was collected from students through validated essay tests and interviews. The data was analyzed by descriptive method. The results show that some of students (1) did not understand the problems, (2) cannot represent the prism and pyramid in other form, (3) did some error in using formula of surface area and volume of prism and pyramid, (4) did some error in calculations and (5) did misconceptions. The causal factors were students did not accustomed to identify and write what known and asked when solve a mathematical problem, difficulty in reading information, did not understand concept of the prism and pyramid, carelessness in calculation, haste in answering questions, and lack of effort.