Animals with selective lesions involving different hippocampal cell fields and/or projections either learned a complex spatial maze postoperatively or were trained preoperatively and tested after the operations. Following damage to anterodorsal CA1 cells and the alveus, acquisition was impaired but performance was normal when the task was learned preoperatively; postoperative acquisition and performance of the preoperatively learned task were impaired in animals with fimbrial lesions. These data suggest that the CA1 cell field and the projections to the subiculum play an important role in the acquisition of new spatial information but that these connections are not necessary for the utilization of spatial information learned preoperatively.