The gene of the Arabidopsis thaliana H+/Ca2+ transporter, CAX1 (cation exchanger 1) was introduced into Japonica cultivars of rice (Ilpumbyeo) by Agrobacterium-mediated transformation, and a large number of transgenic plants were produced. The neomycin phosphotransferase II (NPTII) gene was used as a selectable marker. The activity of neomycin phosphotransferase could be successfully detected in transgenic rice callus. The introduction of the CAX1 gene was also proven by PCR using CAX1-specific oligonucleotide primers in regenerated plants. Stable integration and expression of the CAX1 gene in T0 plants and T1 progeny were confirmed by DNA hybridization, Northern blot analysis, and luminescent analysis.