To investigate the effects of Enterococcus faecium Cernelle 68 on output properties and some haematological and biochemical properties in broiler chicks. 130,male Ross-308 broiler chick's were, used. The animals were divided into two groups as control and experimental 35 mg/kg Enterococcus faecium Cernelle 68 was supplemented to diet of the experimental group. Body weight gain. food consumption and feed efficiency ratio were determined on day 14, 28, 42 and 49. Also on the same days, red blood cell (RBC), white blood, cell (WBC), thrombocyte counts, packed cell,volume (PCV), haemoglobin (Hb) amount and serum creatine,kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), total protein, albumin, triglyceride, cholesterol, and glucose levels were determined from the blood samples of randomly selected 15 animals from both control and experimental groups. After blood samples were taken, carcass weight, small intestine weight and ileum pH of the animals were determined during autopsy. It has been determined that, food consumption was less in probiotic group than in control, and feed efficiency ratio of the probiotic group was higher than that of the control group, but these differences were not statistically significant. The carcass weight of the probiotic group was higher on day 49 (P < 0,05). It has been determined that, the probiotic had no effect on small intestine weight and ileum pH.,No statistically significant change was observed in RBC, WBC, thrombocyte, PCV, and Hb values. AST and ALT levels of the probiotic group decreased statistically on day 49 (P < 0,05). The cholesterol level of the probiotic group was statistically lower than that of the control group on day 14 (P < 0,05). These results show that Enterococcus faecium Cernelle 68 will bring economic advantage to the breeders by improving feed efficiency ratio and carcass weight, and it is safe for the host animal and it is well tolerated by the organism.