An experimental study on the laminar burning velocity of the premixed liquefied petroleum gas (LPG)/hydrogen/air flames was conducted in a constant volume chamber that centrally ignited at various initial pressures (0.1-0.3 MPa) and initial temperature of (308 K). In addition, the tested equivalence ratios of range from (0.8-1.3), and the investigated blends of hydrogen were (0-80%) by volume. Experimental data of laminar burning velocity, flame thickness, stretch rate, and laminar flame speed and combustion pressure of LPG flames with various blends of H-2 have been presented. The constant volume chamber has been designed and constructed specially for this study, as this method considered the most precise one to measure laminar burning velocity. A mixing chamber, ignition control, data acquisitions and high-speed Schlieren photography were used. Experimental results have been shown that the effect of hydrogen addition becomes noticeable when the hydrogen blend is larger than 60%. When hydrogen blending is 80%, adiabatic flame temperature increases about (40 K), the laminar flame speed of LPG also increases from (2.2-4.75 m/s) and laminar burning velocity from (31-59.5 cm/s). While flame thickness decreases from (0.15-0.07 mm) for stoichiometric mixture at atmospheric pressure. Increasing initial pressure from 1 bar to 3 bar reduces the stretched laminar flame speed of LPG-air mixture from (2.2-1.5 m/s), and laminar burning velocity also decreases from (31-20 cm/s). In contrast, combustion pressure increases from (5-25 bar). Equivalence ratio has a more dominating effect on adiabatic temperature, density ratio and flame thickness than hydrogen does. Correlations between hydrogen blend and initial pressure are derived from LPG-air mixtures. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.