Early selection for plant resistance to different special forms of Fusarium oxysporum has been a key goal in conventional and biotechnological breeding. We previously developed a straightforward procedure to differentiate resistant and susceptible field-grown banana cultivars for Fusarium wilt at the leaf level. This chapter presents compiled results from several years of work by our group, developing a method to differentiate resistance and susceptibility to Fusarium wilt vegetative compatibility group (VCG) [01210] race 1 at the leaf level in banana cultivars. This is achieved using the leaf pit bioassay and application of fungal culture filtrates.