Complex multistep problem exercises are one way to enhance engineering students' learning of electromagnetics (EM). This study investigates whether exposure to complex problem exercises during an introductory EM course improves students' conceptual and procedural knowledge. The performance in complex problem exercises is compared to prior success in pre-engineering mathematics and physics courses and with success in the final exam. Students' conceptual knowledge is evaluated with the Conceptual Survey of Electricity and Magnetism (CSEM). The data (N =133) are collected from an undergraduate static field theory course at Helsinki University of Technology, Espoo, Finland. The data are analyzed using correlation and linear regression. The study shows that the complex problem exercises do not improve conceptual understanding of EM. However, complex problem exercises significantly enhance the students' procedural knowledge. In addition, students found problem exercises useful and relevant for their learning. (Contains 2 tables and 1 figure.)