Systemic granulomatous disease involving the spleen, heart, lymph nodes, omentum, liver, kidney, lung, mediastinum, and salivary glands developed in an 8-year-old Rottweiler. The dog also had sialometaplasia of both submandibular salivary glands. Bartonella henselae and B. vinsonii subsp. berkhoffii DNA was amplified from the salivary gland by polymerase chain reaction analysis. Bartonellae may be the cause of this systemic disease, but to the authors' knowledge, involvement of omentum, mediastinum, and salivary glands has not previously been reported in association with Bartonella infection. Bartonellae should be considered potential causes of sialometaplasia.