The aim of this research is to reveal the levels of understanding of student science teachers regarding the digestive system. In this research, 116 student science teachers were tested by applying the drawing method. Upon the analysis of the drawings they made, it was found that some of them had misconceptions such as "the organs of the digestive system have no relationships with each other" and "it is an open-ended structure by which oral nutrients arrive at the stomach". Additionally, it was concluded that some of them had insufficient knowledge. The importance of the findings was analysed in detail in the light of literature information. Suggestions for how to eliminate these problems were provided.