We have investigated the hydrogen absorbing properties of binary TiMn 2 based alloys with the compositions ranging from Ti-56.4 to 66.8at.% Mn, which were prepared by melt quenching and subsequent annealing, as well as arc melting and subsequent annealing for comparison. All the alloys are composed of TiMn 2 and TiMn phases, where the volume fraction of the TiMn 2 Laves phase increases with increasing Mn content. In the annealed alloys with Ti-56.4 to 59.4at.% Mn, the Mn content of the TiMn 2 phase is about 60at.%; whereas in the alloys beyond 59.4at.%, it increases with increasing the Mn content of the alloys. Correspondingly, the hydrogen absorbing capacity of the alloys increases with increasing the Mn content up to 59.4at.%, but rapidly decreases with a further increase of the Mn content. These observations suggest that the alloy composition exhibiting the maximum hydrogen absorbing capacity is determined by a compromise of a high volume fraction and a low Mn content of the TiMn 2 phase. In addition, we found that rapidly solidified alloys exhibited poor hydrogenation behavior. Therefore, it is concluded that the hydrogen absorbing capacity of the TiMn 2 based alloys is mainly governed by the composition of alloy and probably by the atomic arrangement of excess Ti atoms within the TiMn 2 phase.