In this study renal ultrasonographic changes were evaluated in six dogs administered commercial antifreeze (95% ethylene glycol) 2 ml/day/kg of BW, PO, during 3 days. Prior an hour and after antifreeze was applied in 12.,36.,60. and 84. hours totally five times studies were made. Blood and urine samples were collected from dogs besides ultrasonographic examinations. It was evaluated ultrosonographically that within twelfth hours after ethylene glycol administration in 2 dogs and within thirtysixth hours in 4 dogs renal cortical echogenicity increased from mild to middle degrees. On the other hand within sixtieth hours in one dog and within eightyfourth hours in a total of four dogs central medullar regions and corticomedullary junction were sonolucent (Halo sign). While gastrointestinal system irritation and severe calcium oxalate crystaluria for two dogs were observed within 12. hours, oliguria and severe crystaluria for all dogs were determined after 36. hours. Most cli-nicolaboratory values were support to ultrasonographic diagnosis. Ultrasonographic findings were not considered pathognomonic of ethylene glycol nephrosis however, increase of cortical echogenicity within 12. hours can be assessed as primary alteration for oxalate nephrosis.