The aim of the study was to investigate the effects of blog-based learning (BBL) on pre-service science teachers' Internet self-efficacy and understanding of atmosphere-related environmental problems (AREPs). The working group of the study consisted of 89 pre-service science teachers. The participants were divided into groups, and each group was asked to perform the following activities in sequence: (1) accessing scientific documents (e.g. articles, books) and reading them individually, (2) coming together in groups to discuss the scientific knowledge extracted by each group member and preparing a presentation about the issue discussed, (3) sharing findings and engaging groups in a discussion of issues, and (4) developing a blog using the knowledge from the discussions within and between groups. In this study, single-group pretest-posttest experimental design was used. To collect data, the Internet Self-efficacy Scale (ISS), the Atmosphere-related Environmental Problems Diagnostic Test (AREPDiT), and the Opinion Questionnaire about Blogging (OQaB) were used. The results revealed that the subjects' ISS and AREPDiT post-test mean scores were significantly higher than their pre-test mean scores and that their misconceptions about AREPs were substantially eliminated by the intervention. The subjects' responses to the blog use were generally positive.