This research analyzes the problem-solving strategies adopted by math teachers in middle school and explores the role of web-based professional development studies in improving this process. The case group is constituted by twelve math teachers teaching in middle school. These twelve teachers have been arranged a seven-week web-based professional development study in problem-solving strategies. In collecting the data, pre- and post-testing, interview and observation methods have been exercised. On the basis of content analysis, the data obtained have been examined through an inductive strategy.