Rubber seed comprises of 40-48% shell and 52-60% kernel by weight of seed was subjected for oil extraction study. The effects of process parameters such as extraction time (3-12 h), kernel size range (0.5-3 mm), ratio of kernel to solvent (0.03-0.09 g/ml), and variety of solvents (polar and non-polar) on Soxhlet extraction process were studied. Design of experiment (DOE) schemes was considered to prepare an experimental matrix using central composite design (CCD) approach. Response surface methodology (RSM) was applied to optimize the process parameters to achieve maximum oil yield. The maximum oil recovery, 49.36 wt% was obtained during the experiment conducted with hexane as solvent, 0.08 g/ml solute to solvent ratio, average kernel size of 1 mm and 8 h extraction time. Physico-chemical properties of oil obtained from the rubber seed were estimated to measure its suitability for biodiesel production. Proton nuclear magnetic resonance (H-1 NMR) spectra of the obtained rubber seed oil (RSO) revealed 13.17% linolenic, 39.86% linoleic, 27.06% oleic and 19.91% saturated fatty acid in its composition. These compositional data were qualitatively confirmed with Fourier transform infrared (FT-IR), thermal gravimetric (TG) and differential scanning calorimeter (DSC) analyses of extracted oil samples. (C) 2015 Elsevier Ltd. All rights reserved.