Intracameral fibrin formation, a complication of ocular inflammation and intraocular operations, sometimes results in glaucoma and/or corneal damage leading to permanent visual loss. We transferred a therapeutic gene to the corneal endothelium in order to use it as a therapeutic organ. A plasmid encoding tissue plasminogen activator (tPA) was injected into the anterior chamber of rats and electric pulses (EPs) were given subsequently, which transferred a plasmid gene to a highly selected area of corneal endothelium with no inflammation. The biologically active tPA was clearly present for 4 days after treatment. Fibrin formation induced by YAG laser-generated bleeding in the anterior chamber decreased significantly more in treated eyes than in control eyes. Corneal opacity was significantly lower in treated eyes than in control eyes and histological damage was not apparent in the treated eyes. This genetic modification allows us to use the corneal endothelium to treat various ocular diseases and could be a new and effective type of pharmacologic gene therapy.