The purpose of this study is, to examine and investigate why mathematics teachers don't use instructional technology and materials in their mathematics courses. In this study negative effects resulting from the use of materials and reasons of why teachers don't use instructional technology and material in their courses are determined. Case study method was carried out with nine teachers rarely use technologies and materials, working at different schools in Trabzon. It is determined that the most important reason of not using instructional technology and material is growing out of students and teachers don't feel enough themselves for using of instructional technologies and preparing materials. (C) 2011 Elsevier Ltd.