A mechanism consisting of 18 chemical reactions is proposed to simulate the combustion of hydrogen-enriched methane/air mixtures. These include 17 elementary reactions and one global reaction to represent the C2 channel. The simplified reaction scheme has been selected from a comprehensive reaction scheme by using time dependent kinetic flow charts. This technique is also presented in this paper. Good agreements with experimental observations of other investigators were achieved for a wide range of initial conditions. These include 80 KPa <P< 2 MPa, 280 K < T< 650 K, 0.4 < φ< 1.5 and hydrogen to fuel mass ratios,between 0 and 25 percent. A possible explanation for the double peak behavior of the burning velocity along an unhurned gas isentrope. as observed by Miltonand Keck,is proposed.