There has been an increasing tendency to enhance teachers' ability to apply educational technology. Few researchers have investigated with the relationships between the use of interactive whiteboards (IWBs) and the impact on the technological pedagogical and content knowledge (TPACK) of teachers. The purposes of the study were to examine Taiwanese elementary mathematics and science teachers' TPACK with respect to current use of IWBs. Associations between in-service teachers' TPACK and other factors were also examined. The IWB-based TPACK questionnaire was developed and validated in an elementary school context. The results indicated that there were significant differences in the TPACK of elementary teachers who used IWBs compared to teachers who did not use IWBs. Furthermore, elementary science teachers demonstrated significantly higher TPACK than elementary mathematics teachers. No significant difference was found in teachers' TPACK according to gender. The results also showed that teachers' TPACK differed significantly on the basis of teachers' varying amounts of teaching experience. Teachers who had more years of teaching experience demonstrated significantly higher TPACK than did teachers who had fewer years of teaching experience. The research implications of this study are provided along with suggestions. (Contains 8 tables and 1 figure.)