Samples of commercially available epoxidized soybean oil were obtained and the number of functional groups of each epoxidized soybean oil molecule was determined through chemical titration method. The epoxidized soybean is allowed to react with a hydrochloric acid-dioxane reagent at room temperature, converting the epoxy group to the chlorohydrin. An Instron testing machine was used to determine the tensile strength and modulus of the cured resin and composite. Differential scanning calorimetry was used to characterize the curing process and determine the glass transition temperatures of cured resins. A good low cost hardener for the composite has been identified.