Sumatriptan has been used for the acute treatment of migraine attacks. There are many similarities between migraine and epilepsy and the medications used to treat one of these disorders can effectively be used to treat the other. The purpose of this study was to evaluate and compare the anticonvulsant effects of sumatriptan with sodium valproate in NMRI mice. 62 male NMRI mice were divided into 8 groups. The groups consisted of a saline (control) group, 4 intraperitoneally (ip) administered sumatriptan groups (1, 10, 50, and 100mg/kg, ip), and 3 sodium valproate groups (50, 150, and 300mg/kg, ip). 20-min after the injection of either saline or one of the drug doses, pentylenetetrazol (100mg/kg, ip) was injected and seizure parameters were evaluated. The results showed that 300mg/kg sodium valproate markedly inhibited the seizure stage, whereas none of the sumatriptan doses had any significant effect on this parameter. The latency to stages 2 and 4 of the seizures and the interval between the pentylenetetrazol injection to death was significantly increased by both sodium valproate and sumatriptan. Sumatriptan is commonly used for the treatment of migraine and also has a protective effect against seizures induced by pentylenetetrazol in mice.