The absorption-desorption characteristics during prolonged cycling towards hydrogen of composite 95 wt% Mg -5 wt% activated carbon (synthesized from polyolefin wax, a waste product of polyethylene production at low pressure- POW) obtained by ball milling under Ar atmosphere are investigated. Even at first few cycles of hydriding the 95 wt% Mg- 5 wt% POW is reached about 7 wt% of hydrogen absorption capacity and after 80 cycles of hydriding-dehydridng the hydrogen absorption capacity remains high. At the 2nd cycle the sample absorbed 7.1 wt% and 6.4 wt% at 80th cycle. Probably some deterioration of the material occurs because of sintering and oxidation. The presence of activated carbon derived from POW influences positively on hydrogen absorption/desorption properties of magnesium, leading to enhanced rate of hydriding reaction and high absorption capacity during prolonged cycling. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.