A 4-year-old cocker spaniel, male, of 12 kg body weight was presented because of the onset of polyuria or polydipsia. From the first months of its life, the dog had exhibited constant serous to mucopurulent nasal discharge, productive cough, sneezing, reverse sneezing, otitis, and recurrent episodes of fever. The respiratory signs had been treated several times with antibiotics, without ever achieving a complete resolution. Clinical examination revealed normal rectal temperature (38.3°C), increased respiratory rate (40 breaths/min), a copious mucous nasal discharge and right deviation of the heart apex beat (ictus cordis). Increased respiratory sounds with moist rales and crackles were found on chest auscultation. An increase in serum creatinine, urea and phosphorus, hypoalbuminemia and proteinuria were found. Lateral and ventrodorsal radiographs of the thorax and of the abdomen showed the transposition of the heart, with the cardiac apex pointing toward the right (dextrocardia), bronchointerstitial lung pattern, areas of consolidation, lesions consistent with bronchiectasis caves and a mirror-image of abdominal organs, confirming the diagnosis of complete situs inversus (CSI). Respiratory signs, combined with CSI, suggested the diagnosis of Kartagener syndrome (KS). Abdominal ultrasound showed an increase in the echogenicity of the renal parenchyma, a loss of definition of the corticomedullary line, slight bilateral pyelectasis, and decreased cortical perfusion. The dog died 2 months later because of a further worsening of the clinical condition. Necroscopy demonstrated the existence of CSI, rhinosinusitis, bronchitis, and bronchiectasis, so confirming the diagnosis of KS, and renal amyloidosis. This is the first case reported in veterinary medicine of the presence of renal amyloidosis together with KS in a dog.