In the present study we have synthesized chitosan from waste prawns hell via g-irradiation of chitin and subsequent alkaline treatment. The detailed experimental studies demonstrated that nonirradiated chitin deacetylated by 40% NaOH solution showed 72% degree of deacetylation(DD), however 50k Gy irradiated chitin, deacetylated by 20% NaOH demonstrated 81.5% DD. Chitosanin solid state as obtained from g-irradiation of chitin was further irradiated by different doses(2–100kGy) of gamma irradiation and the effects of irradiation on the molecular weight, the rmo-mechanical by differential scanning calorimetry(DSC) and thermogravimetric analysis (TGA), and antimicrobial properties were evaluated with respect to nonirradiated chitosan sample. Gamma irradiation of chitosan with a dose of 100kGy caused a decrease in average molecular weight from1.9_105 to 6.5_104 Da and thus increased its solubility in water. Nonirradiated and g-irradiated chitosan at concentration 1% (w/w) in water were prepared and used to evaluate of its potentiality for growth stimulation of Malabar spinach. The chitosan solution was sprayed on the specimen plants and neighboring soil where germinations were taken place and various plant growth parameters such as plan th eight, number of leaves, leaf areas, dry and wet weight of the plants and roots were investigated. The details study revealed that application of 30 k Gyirradiated chitosan yielded 60% higher growth of the Malabar spinach than that obtained from Nonirradiated chitosan. The data are consistent with preliminary results from field experiments and unambiguously confirms that a minor amount of chitosan has a pro found effect on the growth and development of Malabar spinach.