Dioctophyma renale has been found in dogs, coatis (Nasua nasua, Procyon lotor), ferrets (Galictis cuja, Mustela putorius), otters (Lutra longicaudis), sloths (Choloepus didactylus) and maned wolves (Chrysocyon brachyurus) from the norther, southern and southeastern regions of Brazil. The present report describes two cases of parasitism by Dioctophyma renale in dogs from the southeastern region of São Paulo, Brazil. The kidney worm is the largest nematode known measuring up to 100 cm in length and it is generally located in the right kidney's pelvis, as well as in the peritoneal cavity. Dioctophymosis is characterized by clinical symptoms of urinary complications such as dysuria, urinary obstruction, lumbar pain, renal failure, post-renal uremia, peritonitis and liver damage. Often no clinical signs are evident until late in the disease. Diagnosis can be obtained by finding eggs of D. renale in the urinary sediment, locating the adult parasite within the kidney during ultrasonographic examination, or both. A 4-year-old female boxer (dog 1) and a 6-months-old female whippet (dog 2) were presented to this veterinary hospital showing clinical signs of undereating, weakness, weight loss, moderate abdominal pain and hematuria. Complete blood count and serum biochemistry demonstrated no abnormalities and urine sediment analysis revealed numerous Dioctophyma renale eggs. Ultrasonographic examination showed enlargement of left kidney and tubular structures within the right kidney, suggesting the presence of the parasite. Dog 2 showed also mild signs of peritonitis. Nephrectomy was performed in both cases. One adult worm was found between the liver lobes in dog 2, during the procedure. The peritoneum was flushed with saline solution and the abdominal cavity was routinely closed. Broad-spectrum antibiotics and opioids analgesics were recommended in the postoperative period. Both dogs recovered without complications. As previously described in literature, the animals presented in this report probably were infected by ingesting improperly cooked fish or water contaminated with annelids, as they had access to lakes. The nephrectomy is a curative procedure and it is necessary in the majority of cases because of the severe renal parenchyma destruction. Control measures for this parasitism must rely entirely on prophylaxis, which consists of owners education about the transitions routes, avoiding the dog's free access to risk regions and wild animal's predatory hunting.