An evidence-based, interactive teaching method peer instruction (PI) is promoted to support effectiveness over more commonly used teaching methods. Usually it is proposed for the university and upper secondary school. The research reports on the implementation of the PI approach in teaching subject Science and Technology (S&T) in the 4th grade of primary school. The aim of this research was to verify the feasibility of this approach for much younger students in primary school by evaluating the students' progress in the subject S&T, identifying the differences in individual progress in relation to students' general learning success, and determining students' opinions about the approach and where no desired progress has been made. In a selected Slovenian primary school, a classroom with 26 students (age 9-10) was included in the study and 5 different content areas (Earth's motion, Matter, Magnetism, Forces and motion, and Electricity) were taught using this PI approach. Results show that students made progress in all content areas and no differences were identified in the progress of individual students in terms of general learning success. Students were satisfied with the approach, although more than half of them found the multiple-choice questions as too difficult. Although the PI approach is successful, teachers must be aware that some persistent and widespread misunderstandings may still remain and require additional intervention.