This research is aimed to describe steps of developing mathematics instructional material using contextual approach and guided inquiry method and describe the quality of the developed product. This research is a developmental research with the main steps cover (1) preliminary investigation, (2) design, (3) realization/construction, (4) test, evaluation, and revision, and (5) implementation. The result of validation by expert jugdement shows that the instructional material that is developed is of valid criteria of very good category. The aspects of practicality was of practice criteria of very good category as seen from the implementation of the learning, evaluation by the teachers, and evaluation by the students. The aspect of effectiveness could be reached from the students' achievement and EQ and SQ questionnaire. The result of the test shows that more than 80% of the student achieve the minimum score and percentage many of students who are at a high minimum and very high minimum category increase on EQ and SQ questionnaire. The research produced mathematics instructional material and supporting components, consisting of valid, practical, and effective syllabuses, lesson plans, mathematics module, and the valid, practical, and reliable of test.