This study aimed to explore middle school mathematics teachers' use of mathematics textbooks and examine their integration of tasks in the textbooks into teaching. The framework of a mixed methods research design guided data collection in this study. A questionnaire called the Use of Mathematics Textbooks Questionnaire was developed and validated to identify the ways teachers benefit from textbooks. The results of the study showed that teachers used the student edition textbook for mostly during class and for lesson preparation. Teachers also used the student edition textbook for explaining the topic and the introductory tasks. However, they rarely used it for selecting problems and examples. Teachers read the student edition textbook mostly during and prior to class; and mostly use it for topic explanation, but rarely for problems and examples. They frequently used auxiliary books to select questions similar to the ones in the high school entrance exam problems.