Although much attention has been given to the physics of a microwaveglow discharge, substantially less information is available regarding the chemical effects upon a gas undergoing such excitation. We have studied the chemical effects of a 2450‐Mc/sec glow discharge on several gases and have made quantitative measurements on a few simple molecular systems, e.g., N2, H2, O2, air, CH4. A fundamental relationship has been found to exist between the yield in simple chemical systems and the controllable variables of electric field strength, contact time, and pressure. Analytical expressions for these relationships have been obtained.