Guava, Psidium guajava leaf extract was tested for antioxidant properties and activity; total phenolic content, total flavonoid content (TFC), 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and ferric-reducing antioxidant power (FRAP). Giant freshwater prawns, Macrobrachium rosenbergii were subjected to P. guajava leaf extract coating at concentrations of 0.5 and 1.0%. Controls were left untreated. All samples were individually vacuum packed before chilled storage at 4°C. Total bacteria count and total volatile basis nitrogen were analysed at five day interval during 15 days of chilled storage. The total phenolic content, TFC, DPPH and FRAP values were recorded at 383.67±15.22 mg GAE g-1, 51.02±15.02 mg QE g-1, 77.41±4.28 µM TE g-1 and 2.56±0.44 µM TE g-1, respectively. P. guajava leaf extract glazing was significantly (p<0.05) effective in reducing the total bacteria accumulation in M. rosenbergii. Untreated M. rosenbergii reach the limit of acceptability on 7th day of chilled storage. Meanwhile the shelf-life of both samples coated with 0.5 and 1.0% were extended up to the 10th day of storage. TVBN value of treated samples showed a significantly (p<0.05) lower amount compared to the untreated samples. With regard to safety of food consumption, microbiology analysis are more reliable to reflect on the shelf life prediction of M. rosenbergii coated with P. guajava leaf extract.