The Malaysian medicinal plant, Water Apple’ (Syzygium Aqueum) can provide bioactive compounds that help to support people suffering from many diseases. The present study is undertaken to investigate the phytochemicals and invitro antioxidant activities from extract of Water Apple fruits. Determination of phytochemicals and invitro anti-oxidative capacity, established assay method 2, 2 - diphenyl – 1- picryl hydroxyl (DPPH) radical assay, nitric oxide and superoxide anion scavenging activity assays were used with reference to standard antioxidants ascorbic acid and butyl hydroxyl anisole (BHA).The percentage inhibition of radical scavenging activity increased with increase in concentrations of extract and when compared with standard antioxidants. The results show that the extract of fruits of Water Apple possesses significant antioxidant activity when compared to standard antioxidants. These findings provide a strong rationale to establish Water Apple fruits capability as an anti oxidant capacity. However, in-vivo antioxidant activity and mechanism of action is needed to be further studied.