Male and naturally cycling female rats were tested in a fear conditioning paradigm that encompassed both hippocampus-dependent and -independent components.  The females were both conditioned and tested for retention at the same stage of the estrous cycle, either during estrus or proestrus.  Male rats followed a similar regime as the female rats.  The animals were examined approximately two weeks after conditioning for retention of the spatial-context, and of an explicitly paired conditioning tone.  All animals showed a similar degree of conditioning to the tone.  However female proestrous rats showed less spatial-contextual conditioning than male or estrous female rats.  These results suggest that the changes found during the proestrus part of the cycle are related to hippocampal information processing and not to general changes in learning ability, shock sensitivity, or to state-dependent learning.  The results are discussed and related to previous findings on estrous cycle changes in behavior, anatomy and physiology.