This paper discusses evaluation of hypermedia-based learning environments mainly from the point of view of the learner or student. The evaluation of a learning environment should be based on modern learning theories. These emphasise the importance of constructivism and the learner's activity in building mental models of the mathematical knowledge. The environment should also support conversational and collaborative learning. From the point of view of the learner it should be intentional and provide real life situations and contexts to motivate the study of abstract mathematical contents. Also, it should give sufficient feedback and be able to adapt to the needs of various learners. The purpose of the paper is to discuss basic pedagogical principles that may serve as starting points and guidelines in the evaluation of hypermedia-based learning environments. Two existing hypermedia learning environments will be introduced and evaluated on the basis of the pedagogical principles presented.