Quench of turbulent flame kernel and its incidence factors were studied for methane-air flames. Quench of turbulent flame kernel occurred at large turbulence Karlovitz numbers both for lean and rich flames. Lean flames quenched at higher turbulence Karlovitz numbers compared to rich flames because the Markstein number of lean flames were smaller than those of rich flames. Quench of rich flames may be due to the thermo-diffusive effects induced by the flame stretch. On the other hand, quench of lean flames may be due to the incomplete reaction because of their small burning velocities.