In a study conducted at the Animal Health Unit and Gastrointestinal Sciences, University of Calgary, Alberta, ten healthy, intact, adult male sled dogs received either stanozolol tablets, 2 mg/dog PO, q12h, for 25 days or an intramuscular injection of stanozolol 25 mg on Days 7, 14, 21, and 28. A 15N amino acid ( mmol) was infused intravenously into each dog on Day 0 (before stanozolol treatment) and on Day 31 (after stanozolol treatment). Both oral and injectable stanozolol resulted in significant increases in amino acid nitrogen retention compared to pretreatment values. Oral stanozolol increased nitrogen retention from +/-% to +/- %, while stanozolol injection increased nitrogen retention from +/- % to +/- %. The nitrogen retention action of stanozolol may be beneficial in dogs under stress of surgical trauma and chronic disease.