AbstractAs in the previously reported low‐ and high‐temperature photochemical reactions, preferred formation of CH3Br is observed when a gas mixture of the title reactants is exposed to the action of a “cold” electrical discharge (35°C) or to high temperatures (100‐450°C). The influence of the main reaction variables on product composition is discussed. It is suggested that the mechanism of CH3Br‐formation in the discharge reaction is largely analogous to that operative in the thermal and the photochemical processes. A crucial step in these reactions is the primary attack of a chlorine atom on methane. The different continous‐flow processes have approximately been optimized with respect to their CH3Br yield per pass (discharge reaction: 16%; thermal reaction: 62%). In addition, optimum energy yields with respect to CH3Br formation are compared. Of the four methods tested the high‐temperature photochemical reaction displays the most favorable combination of CH3Br yield and energy yield. The discharge method generally combines a high selectivity and energy yield with low conversions per pass, and may be attractive if recycling of reac