A simplified model for the mutual annihilation of two identical, oppositely propagating premixed laminar flames is examined both numerically and analytically. The conservation equations are derived and their limitations discussed. The various burning regimes are discussed with strong emphasis on the final and most dramatic regime, the ＇＇strong interaction＇＇ or ＇＇homogeneous explosion＇＇ stage. The influence of the Lewis number not equal to 1 on the flame behavior is discussed, specifically, the influence on the excess enthalpy, the flame speed, and annihilation time. Conclusions are drawn that there is a great asymmetry between annihilation for Lewis number greater than 1 and Lewis number less than 1.