The present study was conducted to evaluate the effects of infection of ewes with toxoplasmosis and/or brucellosis on some serum biochemical parameters. Ninety six samples of blood were collected from aborted ewes at different stages of gestation, suspected to be infected with toxoplasmosis and /or brucellosis from different regions in Nineveh governorate. The percentage of toxoplasma and brucella infection depending on Latex Agglutination Test (LAT) and Rose Bengal Test were 21.88% and 23.96% respectively. The results of biochemical analysis showed that infection with toxoplasma caused significant elevation of serum activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH). As well as the concentrations of glucose, total protein and copper. Where as the activity of alkaline phosphatase (ALP) and the concentration of calcium and zinc were reduced. Infection with brucellosis caused a significant increased in serum AST, ALT and LDH, ALP and creatin phosphokinase (CPK) activities, and glucose, zinc and cholesterol concentrations. While serum calcium and total protein concentration were decreased. Association of toxoplasma and brucella infection induced significant elevation of serum AST, ALT and LDH and CPK activities and the concentrations of glucose and copper with significant reduction in serum ALP activity and both calcium and zinc concentrations. It was concluded from this study that infection of ewes with toxoplasma and/or brucella caused changes in some biochemical parameters in the serum.