Economic losses due to mastitis are high in small ruminants herds (Mota, 2008). The decrease in milk production, loss of product quality and sanitary aspects turning the final product unsuitable for consumption are important points related to this disease (Mota, 2008). Carlton and McGavin (1998) claimed that the most serious type of mastitis is the gangrenous type, usually occurring at calving season and affecting variable areas of the udder. It is a very aggressive form of the disease, with high morbidity and mortality (Abu-Samra et al., 1988). Imaging techniques like conventional and Doppler ultrasound have been used to study mammary tumors in dogs, allowing the characterization of malignant lesions in animals (Feliciano et al., 2012; Souza et al., 2013) and women, as well as to differentiate intraductal tumors and debris (Nastri et al., 2011). Studies on mammary gland ultrasonography in animals with mastitis were performed in other species such as cattle (Porcionato et al., 2010) and buffalo (Rambabu et al., 2009); however, ultrasonographic findings related to this disease in goats have not been described. Therefore, this study aimed to describe clinical and ultrasonographic findings on mammary lesions, not yet described in veterinary, of a dairy goat with gangrenous mastitis.