The present study was aimed to determine ascorbic acid, total phenolics and antioxidant activity of five local tomato varieties available in fresh markets, namely “Rashinee”, “Puang”, “Sida”, “Tou” and “Cherry”, under optimum conditions of 2,6-dichlorophenolindophenol, Folin-Ciocalteu reagent and 2,2-diphenyl-picrylhydrazyl radical methods, respectively. Fresh tomato fruits were homogenized and kept as a freeze-dry powder prior to be extracted with methanol, ethanol and deionized water using ultrasonicator as a green extraction method. It was found that the methanol extracts of these samples gave rather higher antioxidant activities (171.6-197.1 mg BHT/100 g dry weight) and total phenolics (302.3-349.7 mg GAE/100 g dry weight) than those of both ethanol and aqueous extracts. It is evident that the total phenolics contents relate well with its corresponding antioxidant activity for all tomato varieties. However, the ascorbic acid contents (37.6-62.9 mg/100 g dry weight) of the aqueous extract could be cooperated as the synergistically reducing factor.