This research aimed to describe the skills grouping and inference on any material oxidation-reduction with a model of the problem solving, for a group of high of medium and low. The subjects were students of class X4 SMAN 4 Kotabumi. This research used the pre-experimental method, a one-shot case study design, and analysis of data statistics descriptive. An research results of analysis learning matter oxidation-reduction with model of the problem solving show that high skill grouping obtained a group of 50% were excellent, 50% were good; to a group being 20% were excellent, 53% were good, and 27% were enough; in the group of low 11% were excellent, 11% were good, 45% were enough and 33% were less. In skill inference obtained a group of high 83% were excellent, 17% were good; to a group being, 20% were excellent, 47% were good, and 33% were enough; in the group of low, 33% were good, 45% were enough, and 22% were less. Penelitian ini bertujuan untuk mendeskripsikan keterampilan mengelompokkan dan inferensi pada materi oksidasi-reduksi dengan model pembelajaran problem solving untuk kelompok siswa kategori tinggi, sedang dan rendah. Subyek penelitian ini adalah siswa kelas X4 SMAN 4 Kotabumi. Penelitian ini menggunakan metode pre-eksperimen, desain one shot case study, dan analisis data statistik deskriptif. Hasil penelitian analisis pembelajaran materi oksidasi-reduksi dengan model pembelajaran problem solving menunjukkan bahwa keterampilan mengelompokkan diperoleh kelompok tinggi 50% berkriteria sangat baik, 50% baik; kelompok sedang 20% sangat baik, 53% baik dan 27% cukup; kelompok rendah 11% sangat baik, 11% baik, 45% cukup, dan 33% kurang. Pada keterampilan inferensi diperoleh kelompok tinggi 83% berkriteria sangat baik, 17% baik; kelompok sedang 20% sangat baik, 47% baik, dan 33% cukup; kelompok rendah 33% baik, 45% cukup, dan 22% kurang. Kata kunci: problem solving, kelompok kognitif, keterampilan mengelompokkan, keterampilan inferensi, oksidasi-reduksi