Öz ÖZET : Cypermethrin’ in Gökkuşağı alabalığı (Oncorhynchus mykiss)’ nın bazı biyokimyasal parametreleri (Alkalin fosfatez, Kolesterol, Glikoz ve Kreatin) üzerine etkisini belirlemek amacıyla, balıklar pestisitin üç farklı subletal dozuna maruz bırakılmışlardır. 15 günlük uygulamadan sonra Alkalin fosfatez yükselip, Kolesterol düşerken, Glikoz ve Kreatin sentetik piretroitin dozlarına bağlı olarak farklı değerler sergilemişlerdir.Anahtar Kelimeler: Cypermethrin, Gökkuşağı alabalığı, Pestisit, Alkalin fosfatez, Kolesterol, Glikoz, KreatinThe Effect of Cypermethrin (A Synthetic Pyrethroid) on Alcaline Phosphates, Cholesterol, Glucose and Creatin of Rainbow Trout (Oncorhynchus mykiss) ABSTRACT : Fish were exposed to three different sublethal doses, in order to determine the effect of Cypermethrin on some biochemical parameters (Alkaline phosphates, Cholesterol, Glucose and Creatine), of rainbow trout (Oncorhynchus mykiss). After 15 days exposured, Alkaline phosphates increased while Cholesterol decreased, Glucose and Creatin took various values depending on the doses of synthetic pyrethroid.Key words: Cypermethrin, Rainbow trout, Pesticide, Alkaline phosphates, Cholesterol, Glucose, Creatine