Tomato (Lycopersicon esculentum) is one of the fruits that contains many antioxidant compounds. Nowadays, there are many organic tomatoes which are produced in Indonesia. The antioxidant activities and the effect of storage time in organic and conventional tomatoes had not been optimally studied. This research is designed to study the antioxidant activity in conventional and organic tomatoes and the effect of storage time on antioxidant activity in both tomatoes. The antioxidant activity, total phenolics, flavonoid content, and lycopene were measured by spectrophotometric method. Vitamin C content was measured by 2,6- dichloroindophenol method. Acetone 80% was chosen as solvent for extraction. The tomatoes were extracted by acetone 80% using maceration with stirrer for 4 hours. Total phenolics and lycopene are higher in organic tomatoes than in conventional tomatoes. Antioxidant activity, total phenolics, flavonoid contents, vitamin C contents and lycopene are affected by storage time. Antioxidant activity showed declines on the ninth day storage in both tomatoes, total phenolics in organic tomatoes showed declines on the sixth day storage but more stable in conventional tomatoes during storage, and flavonoid contents in both tomatoes showed declines on the twelfth day storage, whereas vitamin C contents were stable during fifteen days storage and lycopene decreased after nine days storage.