The aim of this study was to determine learning difficulties and misunderstanding in multipliers and factors of middle school students in Kayseri, Turkey. One hundred and seven students from 6th grade and 48 students from 8th grade were selected randomly from three middle schools for the study. A questionnaire, which was developed by the first researcher, including two open-ended questions, eleven multiple choice questions, and one true-false question was prepared for each group. Students solved each question and explained how they solved them. Also, it was requested verbally to fill in the solutions. Besides these questions, it was requested from the students to answer how they use the subjects of multiplication and factors in their daily lives and how these subjects affected their attitudes and treatments towards mathematics. According to the evaluations of this research, some suggestions were made for students' learning difficulties and concept misunderstanding about multipliers and factors.