In this study the erythrocyte arginase activity of male and female strains of Akkaraman, Morkaraman and Awassi breed sheep located in Elazığ were compared. The erythrocyte arginase activity of blood samples obtained from the sheep strains was mesured by the thiosemicarbazide-diacetylmonoxime urea (TDMU) method. The blood samples obtained randomly from of 10 Akkarman, 13 Morkaraman and 13 Awassi strain animals were used in this study. The results demonstrated that the erythrocyte arginase activity of male and female gender for all strains was statistically significantly different.