Axon-sparing neurotoxic lesions of CA1 or CA3 were produced in the dorsal hippocampus to test dissociative lesion eVects on spatial working memory for sequential items. Rats were required to remember four diVerent sections sequentially presented on a newly devised maze (i.e., Tulum maze) during a study phase. Each section was cued by a unique object that was speciWcally associated with each location within the section during the study phase. Following a 15-s delay and during the test phase, rats were required to revisit the location within a section randomly chosen among the previously visited sections in the absence of the cued object. Both CA1 and CA3 lesions similarly disrupted accurate relocation of a previously visited place. However, diVerential eVects of the CA1 and CA3 lesions were observed in serial position curves. CA3-lesions disrupted performance for the Wrst three serial positions, but did not disrupt performance for the last serial position (recency). In contrast, CA1-lesions disrupted performance for all serial positions. The results suggest that temporal separation of spatial memory may depend on the conjoint function of CA1 and CA3 of the hippocampus with a disruption of a spatial pattern completion process following CA3 lesions and a disruption of a temporal pattern separation process following a CA1 lesion.