The fungal pathogens Sclerotinia sclerotiorum and Phomopsis helianthi are two major diseases in sunflower. While the cultivated sunflower has a narrow genetic base, wild species have been used as a source of disease resistance. In this study. 41 different lines derived from interspecific crosses and inbred line HA89 have been infected with mycelium of Sclerotinia and Phomopsis in 1996 and 1997 and evaluated for resistance. Lines derived from H. argophyllus and H. tuberosus had the lowest Sclerotinia stem lesion. Several lines showing significantly lower Phomopsis stem lesions than the sunflower inbred line HA89 were detected from crosses between HA89 and H. argophyllus. H. tuberosus, H. deserticola and H. xlaetiflorus. BE94-186-02, TUB-5-3235, TUB-5-326 and TUB-1705-327. These inbred lines, derived from interspecific crosses, were resistant to both fungi, hence they are recommended for use in resistance breeding programs.