The prevalence of theileria infection was investigated in 65 goats with suspected symptoms of theilerioses from a private farm in Giza Governorate. In addition, a total of 51 blood samples were collected from apparently healthy goats from private farms and during slaughtering at El-Bassatine abattoir. The incidence of theileria infection in the farm was 86.1% while, the incidence in the apparently healthy goats was 43.1%. Ring form of theileria species was detected in infected erythrocytes. Macroschizonts and microshizonts were detected in the lymphocytes with different shapes of chromatin materials. Haematological studies revealed significant decline in haemoglobin concentration, packed cell volume and red blood cell count. Total leucocyte count showed significant leucopenia in diseased animals. Examination of serum revealed significant rises in levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, urea, creatinine and cholesterol. Concentration of serum total protein, albumin and globulin showed significant decrease in theileria infected animals as compared with the healthy control goats. Levels of serum iron, inorganic phosphorus, magnesium and calcium showed also significant decline as compared with healthy goats. No changes were observed in serum sodium and triglycerides levels of goats with theilerioses. Therefore, it is important to put in consideration the great economical losses caused by theilerioses in such important small ruminants.