In the present paper, exhaust emission analysis was performed among different non-edible oils including Simarouba, jojoba, linseed, and nagchampa with conventional diesel in a diesel engine under different loading conditions. Results show that both oxides of nitrogen (NOX) and carbon dioxide (CO2) increased whereas carbon monoxide (CO), smoke opacity, and hydrocarbons decreased with respect to blend percentage for all prepared test fuels. Simarouba biodiesel may be beneficial for reducing greenhouse gas emissions without any engine modification.