Concept maps (CMs), as pedagogical tools, have well established uses to support teaching, learning, and knowledge assessment. This chapter focuses on the use of CMs as knowledge assessment tools. The CM-based adaptive intelligent knowledge assessment system (IKAS) is described. The kernel of the IKAS is the intelligent knowledge assessment agent which is implemented as a multi-agent system consisting of the agent-expert, the communication agent, the knowledge evaluation agent, and the interaction registering agent. The knowledge evaluation agent compares the teacher’s and the learner’s CMs on the basis of graph patterns and assigns score for a submitted solution. Five-year long experience of developing and using IKAS has resulted in improvements and extensions of the system’s functionality and adaptivity. Evolution of IKAS and its characteristics are summarized. This chapter presents student opinions elicited from questionnaires about CMs as knowledge assessment tools. The results of the practical use of four versions of IKAS in different study courses are described.