Novel therapies that prevent or modify the development of epilepsy following an initiating brain insult could significantly reduce the burden of this disease. In light of evidence that immune mechanisms play an important role in generating and maintaining the epileptic condition, we evaluated the effect of a well-established immunomodulatory treatment, intravenous immunoglobulin (IVIg), on the development of epilepsy in an experimental model of epileptogenesis. In separate experiments, IVIg was administered either before (pre-treatment) or after (post-treatment) the onset of pilocarpine status epilepticus (SE). Our results show that both pre- and post-treatment with IVIg attenuated acute inflammation in the SE model. Specifically, IVIg reduced local activation of glial cells, complement system activation, and blood-brain barrier damage (BBB), which are all thought to play important roles in the development of epilepsy. Importantly, post-treatment with IVIg was also found to reduce the frequency and duration of subsequent spontaneous recurrent seizures as detected by chronic video-electroencephalographic (video-EEG) recordings. This finding supports a novel application for IVIg, specifically its repurposing as a disease-modifying therapy in epilepsy.