Nontuberculous mycobacteria (NTM) are of growing concern as a potential cause of zoonotic mycobacteriosis. NTM are primarily opportunistic environmental pathogens in the same genus as those organisms responsible for human tuberculosis and leprosy. Cats can become infected with NTM, which typically causes localized cutaneous disease, although disseminated or systemic respiratory or GI disease can also occur. This study documented 3 cases of apparently immunocompetent cats with disseminated mycobacteriosis. These cases highlighted that mycobacterial infection can occur in immunocompetent cats and should be considered as a differential in patients with generalized lymphadenopathy or an abdominal mass. Furthermore, cats should be considered potential environmental reservoirs for mycobacteria in human households.