Hydrogen absorption studies have been carried out on the intermetallic compound U(Co_0.3Ni_0.7)Al. Unlike UNiAl which forms a hydride with composition UNiAlH_2.3, the isostructural UCoAl does not absorb hydrogen under moderate conditions. However, hydrogen absorption is found to take place in the Ni substituted U(Co_1−xNi_x)Al alloys, where the Ni content (x) is >0.5. For x=0.7, we find that U(Co_0.3Ni_0.7)Al forms the hydride U(Co_0.3Ni_0.7)AlH_2.2. The hexagonal structure of the parent compound is retained on hydrogen absorption, but there is a shifting of the transition elements from the U plane to the Al plane in the unit cell. While the parent compound U(Co_0.3Ni_0.7)Al is paramagnetic down to 2 K, U(Co_0.3Ni_0.7)AlH_2.2 is an antiferromagnet with a relatively high Néel temperature T_N=70 K. Heat capacity measurements show a decrease in the electronic specific heat coefficient (g) on hydrogenation, implying a reduction in the electronic density of states at the Fermi level.