In this study, a mixed-method design was employed to investigate pre-service chemistry teachers' Technological Pedagogical Content Knowledge (TPACK) development. For effective technology integration in instruction, knowledge about technology is not enough; teachers should have different knowledge types which are content, pedagogical, and technological. The 17 pre-service chemistry teachers who enrolled in the Instructional Technology and Material Development course participated in the study for one semester. The purpose of this course was to learn how to integrate simulations, animations, instructional games, data-logging, virtual labs and virtual field trips into chemistry instruction considering factors such as chemistry subjects and students' possible alternative conceptions or their previous chemistry knowledge. A survey and interviews were used to gather data on the pre-service chemistry teachers' TPACK framework both before and after the semester. A mixed between-within subjects analysis of variance was conducted to examine the differences in the pre-service teachers' TPACK at two time periods considering also the gender factor. For the qualitative data, deductive analysis based on existing codes and categories was applied. The quantitative and qualitative findings of this study revealed that the pre-service chemistry teachers' TPACK improved partially on some components. In addition, based on these findings, gender was not found to be a significant variable in technology integration. For further development in the TPACK framework, more context related technology applications in a learning and teaching environment are needed.