ABSTRACT: A 6-year-old Fuzzy Lop rabbit was referred to a veterinary hospital with a complaint of lameness. In addition to a vertebral subluxation, two radiopaque and well-defined structures were revealed by radiographic evaluation. Ultrasonographically, the masses were characterized as parenchymal structures with diffuse mineralization and formation of reverberation artifacts, suggesting presence of gas. These two structures were excised during a laparotomy and Clostridium tertium was isolated. To the best of our knowledge, this is the first report of C. tertium infection in a pet animal.