Statistical reasoning is needed by students to understanding statistical concepts and problems. Students’ efforts in understanding statistical information and problems often involve statistical process, namely the process of organizing and reducing data and the process of analyzing and interpreting data. This research is descriptive study with qualitative approach that aims to analyze and describe the senior high school students’ statistical reasoning in solving non-routine problems. The subjects in this study were three high school students of grade XII who have same sex and have equivalent mathematical abilities. The instruments used in this study consisted of the Mathematical Ability Test (MAT), the Statistical Reasoning Test (SRT), and interview guidlines. The results showed that students who have low mathematical ability are also reach low level in statistical reasoning. In solving problem related to process of organizing and reducing data, the students reached level 1 and level 2 in statistical reasoning, because the students determine the mode value using incorrect concepts and ways, that are input the data to the mode formula incorrectly, determining the mode value of data which are presented in the frequency distribution table just by looking at frequency column, and cannot combine and sort the data in percent form correctly. In solving the problem related to the process of analyzing and interpreting data, the students reached level 1 in statistical reasoning, because they cannot interpret the tendency of two data groups, so the response which are given is incorrect. Keywords: statistics, statistical process, statistical reasoning.