The purpose of this study was to develop and validate the Pre-service Teacher-Technological Pedagogical Content Knowledge Survey (PT-TPACK) instrument. The PT-TPACK survey items were written to assess preservice teachers' perceptions and understanding of the Technological Pedagogical Content Knowledge construct originally proposed by Mishra and Koehler (2006). The participants for this study were preservice teachers (n = 120) enrolled in a foundations of educational technology course at a mid-sized western university. Data analysis yielded six interpretable factors: pedagogical knowledge (PK), technological knowledge (TK), content knowledge (CK), pedagogical content knowledge (PCK), technological pedagogical knowledge (TPK), and technological pedagogical content knowledge (TPACK). Technological content knowledge (TCK) was the only dimension in the TPACK construct specified a priori that did not emerge. Results from this study suggest that the PT-TPACK survey holds promise as a useful evaluation tool for assessing preservice teachers' knowledge and use of technology to increase the effectiveness of their instructional efforts. (Contains 1 figure and 2 tables.)