In the course of study for development of functional food ingredients from aged black garlic (ABG), heat-treated ripe bulbs of Allium sativum L., the water extracts from raw-garlic (RG) and ABG, and the subsequent organic solvent fractions of ABG were prepared, and their antioxidant, antimicrobial, and antithrombosis activities were compared. The extraction yield of ABG was 4-folds higher than that of RG, and the contents of total polyphenol, total flavonoid, total sugar and reducing sugar in the ABG extract were 4-folds, 1.56-folds, 3.36-folds and 6.75-folds higher than those of the RG extract, respectively. In antioxidation activity assay, the extract of ABG showed minor scavenging activity against DPPH anion, but revealed strong scavenging activity against ABTS cation and nitrite. Especially, the ethylacetate fraction from the ABG extract demonstrated stronger antioxidation activity than the RG extract and other fractions. Although the antimicrobial and antithrombosis activities of the RG extract did not appear in the ABG extract, the ethylacetate fraction from the ABG extract had antibacterial activity against Staphylococcus aureus and Bacillus subtilis, and strong antithrombosis activity via the inhibition of prothrombin, blood coagulation factors and platelet aggregation. All extracts and fractions did not show any hemolytic activity against human red blood cells up to 5 mg/ml. Our results suggest that the ethylacetate fraction of ABG could be applicable to the development of functional food ingredients for antithrombosis agents.