Eimeria infection is one of the most common protozoal disease affecting sheep worldwide. This study was carried out to investigate the effect of Eimeria species (spp.) infection in native sheep breed at Sohag governorate. Total number of investigated sheep was 101. All sheep were examined clinically; blood and fecal samples were collected from each animal. Coprological examination was performed using the standard flotation technique. Eimeria oocysts were counted microscopically using the high power. Oocysts numbers were used to classify the degree of infection into mild and severe. Complete blood picture was performed using automatic blood cell counter. Levels of total protein, albumin, and globulin were determined in sera of infected sheep < em>. In addition to the activities of liver enzymes (ALT, AST, ALP) and serum calciumlevel were measured using the spectrophotometer. Results of hematology and blood biochemistry were analyzed statistically to compare between mild and heavy infections. The total number of sheep infected with Eimeria spp. was 67/101 (66.4%). Infected sheep manifested variable clinical signs such as bloody and/or mucoid diarrhea, dehydration, lethargy, emaciation, fever and loss of wool. In this study, total erythrocytic count and hemoglobin concentration were significantly decreased in heavy Eimeria spp.infection. Total leucocytes count and granulocytes percentage were significantly elevated in mildly infected sheep. While, lymphocyte percentage was increased in case of heavy infection. Total proteins were significantly decreased in case of heavy infection. Albumin/ globulin ratio was considerably altered. The liver enzymes, ALT and ALP were elevated in heavily infected sheep. AST was significantly higher when compared with mild cases. This study highlighted the risk of heavy Eimeriosis that can result in severe anemia and altered liver functions. Therefore, Eimeriosis is a clinical disease of economic importance in productive animals such as sheep.