Along with the adoption of the reform movements, textbooks prepared properly to the mathematics curriculum at all over the world has seen as an effective force in mathematics teaching. Limitation of the studies about the effectiveness and usage of textbooks prepared parallel to the renewal of secondary school curriculum in our country and the results on loosing textbooks’ effectiveness in the last few years has revived the need for conducting the current study. For this reason, it’s seemed an important issue to examine if current mathematics textbooks satisfied to high school students' needs and to investigate the students' reasons for choosing alternative sources. In the research, The Likert type scale developed by the researchers was applied to 170 students randomly selected from two different high schools in Trabzon city. Results revealed that students use alternative sources since they found textbooks somewhat inadequate, they reached easily to the necessary information, these sources consider the individual differences and helping their homeworks. Also students found question types in these sources are more proper to university entrance exams than textbooks.