The results of experimental study of the recombination of hydrogen atoms in a positive glow gap and flowing afterglow of direct current discharge in H2 Ar(0–95%) mixture are presented. On the basis of ESR measurements, the recombination probabilities are obtained for surfaces of quartz and molybdenum glass at different plasma parameters (pressure of 100–400 Pa, discharge current of 5–100 mA) and reactor wall tempera- tures (295–615 K). The values of activation energy for the recombination process are determined and the recombination mechanism is discussed.