A four-year-old red Holstein Friesian cow was admitted to the clinic with fever and milkdrop. Blood analysis revealed the presence of a chronic infection, and the diagnosis of pyelonephritisof the right kidney was made after repeated ultrasound examinations. The animal wastreated with procaine benzylpenicillin, sulfadoxine trimethoprim, oxytetracycline and enrofloxacinebut this therapy was not successful. Nephrectomy was performed after the left kidney provedto have a normal function. The removed right kidney was greatly enlarged and filled with pus.Escherichia coli was isolated from the kidney. The strain was multidrug-resistant, including resistanceto aminopenicillins, streptomycin, sulfonamides and trimethoprim. The cow was treatedwith amoxicillin and clavulanic acid after the operation. Postoperatively, an abscess developedand a tube drain was placed during a second surgery to enable daily rinsing with a chlorhexidinesolution. After a postoperative care period of two months, the animal was sent back to the farm,where it returned to an acceptable level of milk production. This case demonstrates that withbasic surgical skills, a good preparation and knowledge of anatomy, nephrectomy is attainablefor a first-opinion veterinarian, with an acceptable economic prognosis for the farmer.