This study used longitudinal data to investigate the development of preservice teachers' Technological Pedagogical Content Knowledge (TPACK) throughout their initial teacher education program in the United States. Quantitative and qualitative data were collected at four different points in time. Findings indicated that teacher preparation experiences collectively provided preservice teachers' with opportunities to develop their knowledge of teaching with technology from their freshman to their junior/senior year. Opportunities to develop and retain knowledge gains over time, however, were limited in the absence of intentional educational technology coursework. Findings have implications for the design of teacher education programs on the use of technology.