Sicot F-1 is a new cotton variety released in 2004. It has been developed specifically in response to the appearance of a new unique strain of the Fusarium wilt pathogen in Australia. This article describes the identification of introduced germplasm with greater resistance to Fusarium wilt than was evident in local varieties and also in varieties resistant to other strains of the pathogen in other countries. The development of Sicot F-1 from that material is described. The level of resistance is double that of the standard SiCot 189. Fusarium wilt of cotton in Australia, caused by the soil-borne fungus fusarium oxysporum vasinfectum, was first noticed and identified by Joe Kochman on the Darling Downs in 1993. The pathogen is thought to have been present as a native on weeds and well-suited to susceptible varieties of cotton grown through the 1980s. The pathogen is very virulent, capable of killing 100% of plants of a susceptible variety when high levels of inoculum are present. The disease has spread to and identified in all cotton growing regions in eastern Australia except Emerald, lower Namoi, Lachlan Valley and Tandou. Farm hygiene and other Integrated Disease Management practices are also important and are promoted in many venues. This paper describes the identification of resistance and development of a new variety.