Abstract This research aims to increase student mastery of concepts, mastery of science process skills increase student mastery of concepts and relationships of students with his science process skills as applied to problem based learning model instruction in Basic Physics courses. The method used was quasi-experimental. The instrument used consisted of tests mastery of concepts and observation sheet for observing the mastery of science process skills. Subjects were students of the second semester of Chemical Education study program 2012/2013 forces were attending basic physics consists of two classes of 80 students with a number of people. The sample was selected using sampling techniques saturated. The results show there is an increasing mastery of the concept of the N-gain of 0.33 with moderate interpretation, an average of 82.28 students process skills with excellent interpretation and the relationship between student mastery of concepts and skills of its scientific processes (rxy) at a very low 0,042 to interpretation so neglectful. It can be concluded that problem based learning model instruction can improve mastery of concepts and science process skills of students in Basic Physics courses. Keywords: Problem based instruction, mastery of concepts, science process skills Abstrak Penelitian ini bertujuan untuk meningkatkan penguasaan konsep mahasiswa, penguasaan keterampilan proses sains mahasiswa dan hubungan peningkatan penguasaan konsep mahasiswa dengan keterampilan proses sainsnya setelah diterapkan model pembelajaran problem based instruction pada mata kuliah Fisika Dasar. Metode penelitian yang digunakan adalah quasi eksperimen. Instrumen yang digunakan terdiri dari tes penguasaan konsep dan lembar observasi untuk mengamati penguasaan keterampilan proses sains. Subyek penelitian adalah mahasiswa semester II prodi Pendidikan Kimia angkatan 2012/2013 yang mengontrak mata kuliah Fisika Dasar, terdiri dari dua kelas dengan jumlah mahasiswa 80 orang. Sampel yang terpilih menggunakan teknik sampling jenuh. Hasil penelitian menunjukkan terdapat peningkatan penguasaan konsep dengan N-gain sebesar 0,33 dengan interpretasi sedang, ratarata keterampilan proses mahasiswa sebesar 82,28 dengan interpretasi baik sekali dan hubungan antara penguasaan konsep mahasiswa dan keterampilan proses sainsnya (rxy) sebesar 0,042 dengan interpretasi sangat rendah sehingga diabaikan. Dengan demikian dapat disimpulkan bahwa model pembelajaran problem based instruction dapat meningkatkan penguasaan konsep dan keterampilan proses sains mahasiswa pada mata kuliah Fisika Dasar. Kata-kata kunci: Problem based instruction, penguasaan konsep, keterampilan proses sains