Episodic memory relies on memory for the relations among multiple elements of an event and the ability to discriminate among similar elements of episodes. The latter phenomenon, termed pattern separation, has been studied mainly in young and older adults with relatively little research on children. Building on prior work with young children, we created an engaging computer‐administered relational memory task assessing what‐where relations. We also modified the Mnemonic Similarity Task used to assess pattern discrimination in young and older adults for use with preschool children. Results showed that 4‐year‐olds performed significantly worse than 6‐year‐olds and adults on both tasks, whereas 6‐year‐olds and adults performed comparably, even though there were no ceiling effects. However, performance on the two tasks did not correlate, suggesting that two distinct mnemonic processes with different developmental trajectories may contribute to age‐related changes in episodic memory. Episodic memory relies on memory for the relations among multiple elements of an event (relational memory) and the ability to discriminate among similar elements of episodes (pattern separation). The current study examined the developmental changes in both processes in early childhood using age‐appropriate tasks. We found significant improvements in relational memory and pattern separation between the ages of four and six. However, performances on the two tasks did not relate to one another, suggesting that two distinct mnemonic processes may contribute to age‐related changes in episodic memory.