The burning velocities of stoichiometric methane/air, methane/air/exhaust and methane/air/exhaust/reformer gas mixtures have been measured using a constant volume cubical combustion chamber. The flame size and burning velocities were calculated from the chamber pressure record using a multi-zone thermodynamic equilibrium model. The investigation measured the decrease in burning velocity due to addition of EGR and the quantity of reformer gas/air (RG) required raising the burning velocity back to undiluted level. The burning velocity dropped from around 35 cm/s for stoichiometric methane/air mixture to about 13 cm/s if 20% EGR was added to the mix. At about 20% EGR fraction, 42% RG was required to bring back the burning velocity to the original undiluted level.