Memory for emotional experiences often persists longer than memory for neutral experiences. The present study examined how encoding processes influence memory retention across 0.5- or 24-h delays and whether these processes differ between emotionally arousing and neutral information. Participants encoded items during an fMRI scan. Immediately following the scan, and again 24-h later, participants performed a recognition memory test. The results revealed that, for emotionally arousing information, most regions showed a correspondence to subsequent-memory performance that was at least as strong after the long delay as it was after the short delay. For neutral items, by contrast, many more regions, including portions of the hippocampus and lateral prefrontal cortex, showed a stronger correspondence to subsequent-memory performance after the short delay than the long delay. These results suggest that the processes engaged at the moment of encoding have a longer-lasting relation to subsequent memory for emotionally arousing information than for neutral information.