The purpose of this study is to assess students' conceptual learning of electricity and magnetism and examine how these conceptions, beliefs about physics, and quantitative problem-solving skills would change after peer instruction (PI). The Conceptual Survey of Electricity and Magnetism (CSEM), Colorado Learning Attitudes about Science Survey (CLASS), multiple-choice test was administered as a pre- and posttest with Solomon 4 group design to students (N = 138) enrolled on freshman level physics course. The number of chapter taught to the students was 14. Problem-solving strategy steps were asked to students in the exam. The analyses of CSEM showed that the treatment group (g = 0.62) obtained significantly higher conceptual learning gain than the control group (g = 0.36). The conceptual understanding and problem-solving skills of the students on magnetism considerably enhanced when PI was conducted (37% and 20%, respectively). CLASS results for 5 subscales (conceptual understanding, applied conceptual understanding, problem solving general, problem solving confidence, and problem solving sophistication) supported the findings of CSEM.