The purpose of this study was to investigate the effects of scientific discussions based on student-constructed pre- and post-laboratory concept maps on students' attitudes toward chemistry laboratory in the university general chemistry. As part of instruction, during the first four laboratory sessions, students were taught how to construct and objectively score concept maps using a scoring scheme with a symbol system. Then, students were required personally to construct a map prior (pre) and after (post) each of the five laboratory experiments. Concept mapping was used as a tool to carry out the scientific discussions about chemical concepts involved in general chemistry laboratory experiments between instructors and students, and among students. In the experimental group, students (N=45) performed their general chemistry laboratory experiments using individual, small and large group discussions based on pre- and post-laboratory concept maps, whereas the control group students (N=46) performed their laboratory investigations using traditional approaches. A questionnaire of attitudes toward chemistry laboratory (QATCL) developed by the researchers was administrated to both groups to determine the pre-existing differences between the two groups as a pre-test. At the end of the study, QATCL was re-administered to all of the students in both groups to analyze the effect of the intervention on students' attitudes toward chemistry laboratory. The data were analyzed using analysis of covariance (ANCOVA). The statistical results of the QATCL post-test scores showed that there was a significant difference favoring the experimental group. Hence, it is concluded that scientific discussions founded on pre- and post-laboratory concept maps are more effective in improving students' attitudes toward chemistry laboratory than traditional teaching. (Contains 2 figures and 2 tables.)