The process optimization of hydrodeoxygenation of rubber seed oil was investigated on diesel range hydrocarbons selectivity and conversion of reaction intermediates. The comprehensive investigation has been performed on effects of reaction parameters and optimization condition using Response Surface Methodology. The experimental runs were carried out over four operating parameters i.e. temperature (300-400 degrees C), pressure (30-80 bar), weight hourly space velocity (WHSV) (1-3 h(-1)) and H-2: oil ratio (400 -1000 N cm(3)/cm(3)). The reaction intermediates were investigated over optimized reaction parameters for 5 h time on stream. The current study revealed that triglycerides are completely converted into diesel range hydrocarbons to produce hydrodeoxygenation (HDO) selectivity (C16 + C18) of (19.1 wt%) and decarboxylation (DCOx) selectivity (C16 + C18) of (81.7 wt%) under optimized reaction condition at the temperature of 400 degrees C, pressure 80 bar, WHSV = 1 h(-1), and H-2: oil ratio 400 N(cm(3)/cm(3)). Among all the variables temperature and weight hourly space velocity have significantly influenced the hydrodeoxygenation selectivity. In contrast, where the increase in temperature and pressure dropped the decarboxylation selectivity. H-2: oil ratio was observed with significant effect on conversion of transition state of intermediates to stable state of intermediates at optimized condition. The ANOVA analyses demonstrated that HDO selectivity competitively followed on respective reaction condition. (C) 2019 Elsevier Ltd. All rights reserved.