Two of the major fungal diseases of cotton in Australia are fusarium and verticillium wilts caused by the fungus Fusarium oxysporum. F.sp vasinfectum (Fov) and Verticillum dahliae respectively. Both pathogens infect seedlings via the root and cause wilting, stunted growth and for Fov, death of some plants. In Australia Fov is the major cause of crop losses due to fungal infection, however, the incidence of verticillium wilt has increased recently due to the planting of susceptible varieties (Johnson and Nehl, 2004). We have been studying NaD1, a naturally occurring antifungal protein from the ornamental tobacco (Nicotiana alata) (Lay et al 2003). NaD1 is a member of the plant defensin family, a group of small, basic peptides with similar 3-D structures (Thornma et al 2002). Plant defensins have a range of antifungal activities. Several plant defensins, when expressed in transgenic plants, enhance resistance to pathogen attack (Bart et al, 2002), and field trials by Monsanto, of transgenic potato expressing an alfalfa defensin, have demonstrated resistance to Verticillum dahliae in some lines (Gao et al. 2000). In a program funded by Hexima Ltd, we have produced transgenic cotton plants expressing NaD1 under the control of the 35S promoter. Four lines, carrying single copies of the Gene, were selected for further analysis. Expression of NaD1 was high in most plant tissues tested.