Pattern separation is a key component of episodic memory as it allows us to distinguish between similar events that share overlapping features. Therefore, understanding the development of pattern separation processes can help elucidate individual differences in memory development. Research in children and adults has shown relations between hippocampal structure and pattern separation, indexed behaviorally through a mnemonic discrimination task where participants distinguished between similar stimuli. However, there has been less research investigating relations between hippocampal function and pattern separation processes, all in adult samples. Thus, the current study sought to pilot a child-friendly mnemonic discrimination fMRI paradigm in adults before recruiting a child sample. Results provided some evidence of pattern separation processes as greater differences in activation for Targets relative to Lures predicted better memory performance. Future studies will recruit a child sample to assess group differences in pattern separation processes as well as go beyond mean activation for the conditions by using techniques such as representational similarity analysis to assess patterns of representations for Targets, Lures, and Foils across the voxels of the hippocampus.