The objectives of this study were to evaluate the effects of live yeast culture supplementation as a natural feed additive on fattening performance, some blood and rumen fluid parameters in male goats. Totally 48 hybride male goat kids (Saanen x Sami breeds) were divided into one control and three treatment groups each containing 12 kids. Concentrates of groups were formulated as isonitrogenic and isocaloric. Live yeast culture (RumiSacc, Integro Food Industry and Trade Co., Istanbul, Turkey; Live yeast cell: 1.4 x 10(8) cfu per gram) was included in the concentrates at 0 (CON), 1.5 (YC15), 3.0 (YC30) and 4.5% (YC45) on fed basis, respectively. Concentrates were given ad libitum and 100 g per day per animal of lentil straw was given as roughage. Dietary yeast culture at the level of 4.5% increased total weight gain (+15.5% regarding control group). Rumen ammonia-N level was increased with 3 and 4.5% of live yeast culture (+30.9 and +30.5% regarding control group). Ruminal total and individual VFA and blood plasma levels of total protein, albumin, urea nitrogen, total cholesterol, triglyceride and the activities of alanine amino transferase, aspartate amino transferase and gamma-glutamyl transferase were not affected from the dietary treatments. Coliform bacteria count in ruminal fluid and faeces was decreased with yeast culture supplementation. It is concluded that live yeast culture can be included in male goat diets at the level of 4.5% with positively affecting performance.