While engines fueled with neat or blended biodiesel have favorable combustion-emission profile in terms of carbon monoxide, particulate matter and unburned hydrocarbons emissions, they are reported to have higher NOx emissions as compared to petro-diesel. On the other hand, use of alcohols especially methanol, though limited in diesel engines, is found to decrease engine exhaust emissions including smoke and NOx emissions. The present experimental investigation evaluates the use of biodiesel-methanol blend in mitigating higher NOx emissions in biodiesel fuelled engines along with its effect on other engine performance conditions. The experimental results obtained for a blend of 90% Jatropha methyl ester and 10% methanol (J90M10) and neat Jatropha methyl ester (J100) by varying engine output load at maximum torque speed of 1400 rpm are analyzed and discussed in this paper. The experimental results at full load operation for J90M10 blend compared with neat J100 indicate a reduction in exhaust nitric oxide and smoke concentrations by 28% and 50% respectively along with a reduction of 2 % in peak pressure and 0.5 % in brake thermal efficiency. Also, a marginal retard in injection timing and a higher ignition delay period is observed with Jatropha methyl ester-methanol blend operation. Copyright © 2012 by ASME.