Introduction: It is suggested that repetitive seizure attacks lead to the hippocampal neuronal damage and memory impairments. Some therapeutic effects, including analgesic, neuroprotective, antioxidant and anticonvulsant properties, of Nigella sativa (NS) have been reported. In the present study, the effects of hydro-alcoholic extract of NS were investigated on spatial memory damage in penthylenetetrazole (PTZ)-induced seizures in rats. Materials and Methods: Male Wistar rats were divided into five groups: group 1 (control group) received saline. The animals in group 2 (PTZ group) were treated by saline and were injected by PTZ (50mg/kg, ip). Groups 3 (PTZ+NS 100), 4 (PTZ+NS 200) and 5 (PTZ+NS 400) were treated by 100, 200, and 400 mg/kg of NS extract (ip), respectively, 30 min prior to each PTZ injection for 5 consecutive days. Finally, the animals were examined by Morris water maze test. Results: The animals of PTZ+NS 100, PTZ+NS 200, and PTZ+NS 400 had significant lower seizure scores compared to PTZ group. The latency to the onset of seizures were also significantly higher in these groups than that of PTZ group. In Morris water maze test, the time spent and traveled distance in target quadrant by the animals of PTZ group was lower than that of control group. Pretreatment by all doses of the extract increased the time spent and traveled distance in target quadrant compared to PTZ group. Conclusion: The present data suggest that the hydro-alcoholic extract of NS possesses beneficial effects on spatial memory impairments in PTZ seizures model.