Argumentasi ilmiah penting untuk dikembangkan karena dapat melatih berpikir secara ilmiah, berkomunikasi, dan bertindak seperti ilmuan. Penelitian ini bertujuan untuk mengetahui kemampuan argumentasi ilmiah dan mendeskripsikan profil kemampuan argumentasi ilmiah siswa berdasarkan indikator. Penelitian melibatkan siswa kelas VIII B SMP Negeri 9 Salatiga sebagai subyek penelitian yang ditentukan melalui teknik purposive random sampling. Materi pelajaran yang dipilih adalah zat aditif dan zat adiktif. Teknik pengumpulan data menggunakan observasi, tes, dan wawancara. Instrumen penelitian dikembangkan dan diuji validitas isi dan konstruk. Data dianalisis secara kuantitatif dan dideskripsikan secara kualitatif dengan teknik triangulasi. Tahapan analisis data meliputi pengumpulan data, reduksi data, display data, dan pengambilan kesimpulan. Hasil penelitian menunjukkan bahwa subyek memiliki kemampuan argumentasi ilmiah dengan kategori sangat baik (5%), baik (46%), cukup (41%), dan tidak baik (8%). Diketahui bahwa profil kemampuan argumentasi ilmiah siswa berdasarkan indikator secara berurutan yaitu kemampuan pada claim (skor rata-rata: 2,68), rebuttal (skor rata-rata: 2,4), data (skor rata-rata: 2,24), dan warrant (skor rata-rata: 1,33).Kata Kunci: Argumentasi Ilmiah; Indikator Claim, Data, Warrant, RebuttalScientific arguments are essential to developing because they can train to think scientifically, communicate, and act like scientists. This study aims to determine the ability of scientific argumentation. Moreover, describe the ability of students to scientific argumentation based on indicators. The study involved students of class B 8th grade in Junior High School 9 Salatiga as research subjects determined through a purposive random sampling technique. The subject matter chosen is additives and addictive substances. Data collection techniques using observation, tests, and interviews. The research instrument was developed and tested for content and construct validity. Data were analyzed quantitatively and described qualitatively by triangulation techniques. Stages of data analysis include data collection, data reduction, data display, and conclusion making. The results showed that the subjects had the ability of scientific argumentation with top categories (5%), good (46%), sufficient (41%), and not good (8%). It was knowing that the profile of students' scientific argumentation abilities based on indicators in a sequence is the ability to claim (average rating: 2.68), rebuttal (average rating: 2.4), data (average rating: 2.24), and warrant (average rating: 1.33).Keywords: Scientific Argumentation; Indicators Claim, Data, Warrant, Rebuttal