Issues critical for research on conceptual change in students are reviewed, drawing on a body of research with children and adolescents aged 5 to 16 years. Issues are examined in light of science education. It is proposed that science education should aim at fostering in students the development of ways of looking at phenomena that are as close as possible to those identified by scientific disciplinary knowledge, and that the process by which this happens can be described in terms of the restructuring and structuring of students' conceptual networks. The role of metalearning requires further study, since it is apparent that conceptual change requires that the student reflect on his or her own learning. The process of metalearning can be stimulated by discussion with peers and the teacher, but it also requires the individual's independent action. Metalearning activities should be started at the elementary school level. Another research issue is the evaluation of conceptual change. Not all methods are suitable for evaluating conceptual change. Accurate monitoring of change will require a wide range of different types of data. Implications of these findings about conceptual change for classroom practice, learning environments, testing strategies, the design of learning paths, and teacher education are considered. There is a 23-item list of references. (SLD)