A recent review of literature in topic of rate of change mostly highlighted students and teachers' difficulties in handling conceptual questions. This initiated the researcher to investigate the Malaysian pre-service mathematics teacher's subject matter knowledge in rate of change through a case study design. A task-based interview was conducted with Chong, a pre-service mathematics teacher that majored in mathematics. There are 6 tasks given, comprising topics of rate of change and derivatives. The result shows that Chong has difficulties dealing with derivatives caused by his lacking knowledge in rate of change conception. His interpretation of rate of change under multiple contexts were also inaccurate, even for motion graphical context. His weakness in graphical representation also reflected his insufficient knowledge in rate of change as he was unable to convey the first principle accurately. The overall result suggested that Chong's subject matter knowledge of rate of change is insufficient, especially in meaning of rate of change, describing the occurrence of rate of change, and distinguishing between rate of change and instantaneous rate of change.