Abstrak: Penelitian ini bertujuan untuk mengetahui keadaan miskonsepsi siswa sebelum dan sesudah dilakukan treatment berupa wawancara klinis berstruktur konflik kognitif berbantuan media lego. Bentuk penelitian ini adalah Didactical Design Research (DDR) yang terdiri dari tiga tahapan, yaitu: (1) tahapan analisis disain didaktis, (2) tahapan analisis metapedadidaktik, dan (3) tahapan retrosfektif. Sampel dipenelitian ini adalah 4 siswa kelas VII G SMP Negeri 5 Pontianak. Instrumen tes yang digunakan sebanyak 3 kali, yaitu pretest, posttest pertama dan posttest kedua. Ditemukan 10 bentuk miskonsepsi pada saat pretest, 1 bentuk miskonsepsi saat posttest pertama dan tidak ditemukan lagi miskonsepsi pada posttest kedua. Miskonsepsi setiap subjek mengalami penurunan yaitu pada posttest pertama sebesar 91,67% dan pada posttest kedua sebesar 100% ini artinya wawancara klinis berstruktur konflik kognitif berbantuan media lego dapat mengatasi miskonsepsi siswa pada materi operasi pecahan.   Kata Kunci: Wawancara Klinis, Konflik Kognitif, Media Lego, Miskonsepsi   Abstract: This research aims to find out how the student’s misconception before and after treatment (clinical structured interview through cognitive conflict with lego). This Didactical Design Research consists of three steps, (1) Design Didactical Analysis, (2) Metapedadidaktik Analysis, and (3) Retrosfektif. The sample of this research were 4 students of class VII G SMP Negeri 5 Pontianak. One pre-test was initially held to know the students’ prior knowledge, afterwards, two consecutive post-tests were held in order know the success of the treatment and the significant effect of the treatment respectively. This research found 10 misconceptions when the pretest was held. Likewise 1 misconception was found when the first posttest was held, however no misconception was found when the second posttest was held. Since misconception in every subject was decreased, in first posttest was 91.67% and in second posttest was 100%, it means clinical structured interview through cognitive conflict with lego can overcome student’s misconception on fraction operation.   Kaywords: clinical interview, cognitive conflict, LEGO, misconception