The purpose of the study is to investigate the obstacles of teaching mathematics faced by the class teachers in Jordan. To achieve this purpose a study sample of 192 male and female class teachers was selected randomly from government schools. The instrument of the study was a questionnaire used to investigate the obstacles of mathematics teaching. The results of the study revealed that the class teachers faced obstacles in teaching mathematics in the following domains: planning for teaching mathematics, executing mathematics lesson and assessment. There were no significant differences in the obstacles of teaching mathematics faced by the class teachers due to the teachers' gender or class level (first grade, second grade, third grade).