An 11-year-old female mixed-breed dog admitted due to anorexia and vomiting. Radiography showed 7.6-mm uroliths in the right proximal ureter and an enlarged kidney. Type 1 emphysematous pyelonephritis (EPN) was diagnosed using computed tomography (CT) in the awake dog. Right ureteronephrectomy was performed, and Escherichia coli was isolated. The stone was consisted of 80% calcium oxalate. At the 6-month follow-up, no complications were observed. This is the first report of EPN caused by calcium oxalate in a dog. In addition, we suggest performing CT in weak animals to diagnose EPN without anesthesia.