If we truly value the development of knowledge, skills, and attitudes that are unique to practical work in science laboratories, appropriate assessment of these outcomes must be developed and implemented continuously by teachers in their own laboratory-classrooms. The National Science Education Standards (NRC, 1996) indicates that all the student’s learning experiences should be assessed and that the assessment should be authentic. Attention to such standards, however, has promoted testing that has generally not incorporated the assessment of performance and inquiry, although there have been a few noteworthy efforts to do that. Researchers, teachers, and testing jurisdictions whose goal is to assess comprehensively the learning that takes place in school science generally, or in school laboratories more specifically, should use appropriate assessment tools and methodologies to identify what the students are learning (conceptual as well as procedural). The effects of such experiences on students’ interest and motivation should also be assessed.