Sharp-wave ripples are components of the local field potential in the hippocampus that are characterized by short oscillatory activities at high frequency (about 100-250Hz) during slow wave sleep. At the neuronal level, reactivation of awake experience in the hippocampus during sharp-wave ripple events has been proposed to be a neural mechanism for memory consolidation. In recent studies, the sharp-wave ripple events are have been also observed during the awake quiescent state immediately before or after the learning task. Furthermore, the interaction between the hippocampus and the prefrontal cortex is also important for memory consolidation. However, the interaction of the hippocampal ripple and prefrontal activities during learning stage has not been established. In this study, we recorded the hippocampal local field potential during the delayed reinforcement task that is one type of memory retention test and analyzed the sharp-wave ripple events. After the recording, number of ripple events was detected from hippocampal local field potential during delay period of the task and were analyzed separately for correct trials and incorrect trials. In the correct trials, number of the ripple events immediately before reward cue during delay period was increased and the peak of the number of events was correlated with performance of the task significantly. In contrast, number of ripple events during incorrect trials showed no significant change. In addition, prefrontal theta activities after hippocampal ripple events were increased at term of immediately before reward cue. The ripples before reward cue may reflect the neuronal activities for a reward related memory recall or memory consolidation involving prefrontal function.