The rabbit defensin gene NP-1 was introduced into embryonic callus cultures of three maize (Zea mays L.) hybrid lines by particle bombardment, and transgenic plants were obtained. Genomic PCR and DNA dot blot analyses confirmed that the NP-1 gene was integrated into the genome of the regenerated T0 maize plants. Genomic PCR and Southern blotting results revealed that the NP-1 gene was transmitted stably from the T0 to the T1 generation. RNA dot blot analysis verified the transcription of the NP-1 gene in T1 plants. When challenged with northern corn leaf blight (Helminthosporium turcicum Pass), the T1 plants expressing the NP-1 gene showed greatly improved resistance to the fungal disease compared with the wild-type maize plants.