This study aims to determine the opinions of teacher candidates about using history of mathematics (HoM) in the instruction of mathematics. Research data was collected from elementary mathematics education 4th grade students through semi-structured interviews conducted for the purpose of collecting their opinions about using HoM in the instruction of mathematics. The data of this study conducted with qualitative approach was collected from six teacher candidates. The review of semi-structured interviews revealed that teacher candidates believe that using HoM in the instruction of mathematics may be useful for both teaching and learning purposes. Their concerns about using HoM in the instruction of mathematics are another outcome revealed by the study. Regarding the results, it is suggested to teach the courses of elementary mathematics education's undergraduate program that are related to educational content knowledge along with the activities of HoM.