It is well established that the septo-hippocampal system is involved in memory. The medial septum is connected to the hippocampus via the fimbria fornix, which consists mostly of acetylcholine and ã-aminobutyric acid (GABA) projection neurons. The contributions of the cholinergic projection to memory have been studied extensively; whereas, the role of the GABAergic projection is not well characterized. The present experiment tested whether septal infusions of the selective H-channel blocker ZD7288 would impair spontaneous alternation (SA) and continuous multiple inhibitory avoidance (CMIA). Fifteen minutes prior to assessing SA or CMIA, different groups of male Sprague-Dawley rats were given septal infusions of saline or ZD7288 (0.2, 0.6 or 1.5 nmol / 0.5ìl). Our results indicate that septal infusions of ZD7288 impaired SA in a dose-dependent manner; the same infusions did not affect CMIA. This is the first demonstration that H-channels on septo-hippocampal GABAergic projection neurons are involved in memory.