This study investigated changes in inservice teachers' technological pedagogical content knowledge and technology integration self-efficacy as a result of engaging in collaborative instructional design with Web 2.0 tools. We collected survey and interview data in the pre/post format, and teaching portfolios served to triangulate survey and interview results. We observed improvements in both perceived technological pedagogical content knowledge and technology integration self-efficacy. Interestingly, the successes in implementing learning activities recorded in the teaching portfolios were attributed to the collaborative nature of instructional design, whereas the perceived weaknesses were attributed to personal planning skills. Although these findings cannot be generalized to the larger population, our results suggest that instructional design 2.0 can be a useful professional development activity for inservice teachers.