Caecal coccidiosis was determined in 12 white Leghorn chickens aged 18 weeks. Macroscopically slight thickness, congestion and petechie were observed in the caecum. The lumen of caecum was full of blood and, necrotic areas were seen on the mucosal surface due to the damagae of villi epithelisl cells. Microscopically it was observed that erythrocyte, epithelial cells and forms of parasites were present in the lumen of caecum due to the damage of villi epithelial cells. Lymphocyte, plasma cell and heterophil cell infiltrations were found in the propria mucosa as well as gangrenous typhilitis containing focal necrosis.