Given the relevance of students’ risk education about occupational safety and health (OSH), the need for reliable assessment tools for learning evaluation is widely advocated. However, multiple-choice tests or inventories show several limitations, including the emphasis on basic definitions instead of organized conceptual systems and passive tool to inspect how students actively organize and represent the acquired knowledge in line with the theory of meaningful learning. A concept map specifically developed in the field of risk education and its quantitative scoring protocol are here proposed. Then, a case study with a pre- post-test design is presented, including 611 upper school students who undertook an OSH-related risk educational course. The findings are briefly discussed and help identify the possible information we can get from concept maps in terms of problem-based learning.