In this paper, the effects of hydrogen-blended LPG on performance, combustion, and emission behavior of mahua oil-fueled dual fuel engine were experimentally investigated and presented. Mahua oil (pilot fuel) was directly injected into the cylinder during compression stroke and gaseous fuels LPG and HLPG (primary fuel) was inducted into the intake manifold during suction stroke of the engine with variable flow rates such as 1,2,3, and 4 lpm (liter per minute) at 1-lpm interval. The investigation was carried out on diesel engine at speed of 1500 rpm with 3.7 kW rated power output. The following inferences were made from the experimental investigation. Brake thermal efficiency of the engine decreases for alternate fuel (neat mahua oil) mode of operation compared to conventional diesel fuel operation. On the other hand, brake thermal efficiency of neat mahua oil increases from 28% with single fuel operation to 29.3% under 5 lpm LPG dual fuel operation. Further improvement in brake thermal efficiency is noted when 1 lpm hydrogen is mixed with LPG flow. Eighty-three percent reduction in HC emission is observed for 11 lpm HLPG compared with 10 lpm LPG. Massive reduction in smoke formation is perceived for both LPG and HLPG flow rates. But NO emission is increased for both LPG and HLPG fuels compared to neat mahua oil. As a final point, the study abstracts that performance of the neat mahua oil-based compression ignition engine has been increased under dual mode by adding LPG and hydrogen. © 2019, © 2019 Taylor & Francis Group, LLC.