The difficulties that we have experienced in teaching and learning mathematics that exist in every moment of our lives stand as our limitation in achieving the desired level of mathematics success. One of the elements of a qualified mathematics teaching methods. Researches show the effectiveness of teaching methods on mathematics teaching at different levels and subjects. The dicersity of teaching methods is an impotant element in attracting students’ attention, freeing them from prejudice and consequently increasing their mathematics achievement. Based on this reason, in this research, were to research the effects of teaching supported with Realistic Mathematics Education (RME) on 4th grade students’ achievements of “length measurement” and the recall of acquired knowledge with the method of RME. Pre test-post test control grouped half experimental pattern were used in the research. The sample of study which processed of 2013-14 years consists of 46 students who participated 23 students from experimental and 23 students from control groups. Lessons were carried on with RME in experimental group and in line with the activities included in MEB primary school mathematics course curriculum in control group. “Mathematics Achievement Test” resorted on the topics of measuring lenght for measuring students’ achievement. Before the application, pre-test and after the lesson post-test was applied and 4 months later permanency test was applied to both experiment and control groups. The quantitative data from the achievement test were analyzed by paired-samples t test and Independent samples t test in SPSS 13.0 package program. Results of the study proved that teaching supported with RME method used with the experiment group at the teaching of “length measurement” improved the success of the students and affected the recall of the acquired knowledge.