This study was carried out on 40 pregnant toxaemic native breed ewes. They were obtained from a private sheep farm in Sharkia Governorate and 10 clinically healthy pregnant ewes from another farm (served as a control group). All animals were in a late stage of pregnancy This work was done to study clinical and biochemical changes in ewes suffering from manifestations of pregnancy toxaemia as these alterations may help prediction of the disease. The diseased ewes were divided into two groups according to clinical findings: Group 1: Moderately affected. Group 2: severely affected, each group comprised 20 ewes. The clinical findings were recorded. Two blood sample were taken from each of the healthy control and the diseased animals. First blood sample was taken on sodium salt of EDTA for hematological studies. TRBCs and TWBCs counts, Hb concentration and PCV were increased significantly              (P ≤0.01) in the two groups compared to the healthy control. Second blood sample was collected in a clean centrifuge tube where serum was separated for biochemical examinations. Total ketone bodies –ALT-alkaline phosphatase and free fatty acids were increased significantly compared to the control group-But glucose –calcium levels-total protein –albumin-globulin-total cholesterol and triglycerides were decreased significantly compared to the control group. Urine examination indicated the presence of ketone bodies, glucose and protein in pregnant toxaemic ewes compared with the healthy control ones. It could be concluded that high concentration of ketone bodies in blood and urine in addition to hypoglycemia are markers of pregnancy toxaemia and their presence deserves early interference to safe the animal's life.