Students seem to have difficulty in fractions is an evidence of poor understanding or misconception. Understanding the concept of fraction is important for students to perform the procedure algorithm. Since teachers are the first-hand person by which students learn formal mathematics in our country, it is very important for teachers to identify the understanding of concepts and misconceptions about fractions to further improve conceptual understanding and overcome misunderstandings of the concept. Therefore, a study aimed to assess trainee teachers' levels of understanding in fundamental fraction knowledge was conducted. The participants in this study consisted of 23 trainee teachers that enrolled in a 4-years teacher education program in Mathematics major at Raja Melewar Teachers' Training Institute, Seremban. The instrument used in this study is Incorporating Fraction Knowledge Test, adapted from Chelsea Diagnostic Mathematics Tests. The findings show that the level of understanding of fraction among trainee teachers is at a moderate level. This implicated that there is a need for elevating trainee teachers' knowledge in fraction.