Two experiments were carried out to evaluate the effects of feeding Aspergillus oryzae(AO) ferment on performance, intestinal microflora, serum components, ammonia generation and litter dampness in broiler chicks. In experiment I, three hundred sixty, one day old broiler chicks, Abor Acres, were fed 0 and 0.1% of Aspergiilus oryzae short conidia ferment(AOS) and 0.1% of Aspergillus oryzae long conidia ferment(AOL) for five weeks. In experiment II, three hundred sixty, one day old broiler chicks, Abor Acres were fed 0, 0.1 and 0.2% of Aspergillus oryzae long conidia ferment(AOL) for five weeks. In experiment I, growth rates were not statistically different among dietary treatments. AOS and AOL showed increased tendency in weight gain and feed intake compared to those of control, whereas feed conversion was not different. Litter dampness of AOS and AOL was also tended to decrease compared to that of control, but was not significantly different. Fecal ammonia gas generation was decreased in feeding AOS and AOL, and maintained 1/2 to 3/4 compared to the control. In serum metabolites, AOS and AOL increased glucose and calcium, and decreased total protein, blood urea nitrogen and total cholesterol. In experiment II, body weight of chicks fed 0.1 and 0.2% AOL were heavier than the control(P<0.05). Feed intake of chicks fed 0.1 and 0.2% AOL also were higher than the none, but feed conversion ratio was not different among treatments. Ileal and cecal microflora showed increased tendency in lactic acid bacteria compared to those of the control. Salmonella and E. coli were decreased in ileum of chicks fed 0.1 and 0.2% AOL. In conclusion, feeding AO ferment increased growth performance and improved intestinal microflora of broiler chicks and environments of broiler house.