The methanolic extracts in each growth stage (tillering, panicle initiation, booting, milking, and maturation stage) from 14 kinds of Thai leaf rice cultivars (white, red, and black rice) are studied for their antioxidative activities and total phenolic contents. The total phenolic content of these extracts was analyzed by Folin-Ciocalteau method, and antioxidative activity was assessed by the 1,1-diphenyl-2-picrylhydrasyl (DPPH) free radicalscavenging activity, the inhibition of lipid peroxidation and metal chelating ability. The results revealed the highest total phenolic content in milking stage of methanolic extract from all white, red, and black rice (0.709-0.743, 0.948-0.991, and 1.061-1.132 mg GAE/mg of extract, respectively). Furthermore, milking stage of methanolic extracts also showed the greatest capability in antioxidant activity which black rice (Entry 18) indicated the highest potential in scavenging DPPH radicals and calculated in terms of IC ₅₀ (IC ₅₀ = 0.048 mg/mL) and lowest in white rice (Jasmine 105) (IC ₅₀= 0.556 mg/mL). In contrast, metal chelating ability was found in all stage of Thai rice cultivars (white, red, and black rice) in the range of 0.02-0.08 and 0.03-0.19 mg/ml, respectively. These findings suggest that milking stage of black rice should be developed further to be useful in food industry or health products. © Research India Publications.