Objective Transplant genetically engineered cell lines to synthesize and release GABA by immortalized neural progenitor cells (INPCs) in rats, can survive and differentiate in the hippocampus in the epileptic rats model induced by pilocarpine, have ability to suppress spontaneous seizures. Methods The INPCs were transfected with the GABA-synthesizing enzyme GAD (65) cDNA( INPCs-GAD65), Labeled INPCs-GAD65 with superparamagnetic iron oxide (SPIO), SPIO-labeled cells were tracked with 1.5T MRI scanner in vivo; Behavior were monitored for 6 days after surgery;The change examined with the electroencephalogram recording;The differentiation of transplanted cells was observed with immunohisochemistry. Results Animals that received genetically engineered GABA-producing cells had significantly fewer spontaneous seizures than did that the control animals, Epileptiform spikes was suppressed significantly in the electroencephalogram recording; 1.5 Tesia MRI in vivo displayed that remarkable low signal area on T2WI was seen in the fight brain which transplanted with SPIO-labeled cells. SV40Tag-positive cell can change into neurons and astrocytes in the hippocampus. Conclusion These data demonstrate that genetically engineered cells could suppress spontaneous seizures in an accepted model of temporal lobe epilepsy. This is an important step toward defining a clinical potential for this approach in epilepsy. Key words: Epilepsy; Neural progenitor cells; Transplantation; GAD65