It is shown that Gd-zeolites have a catalytic activity towards ethylene hydrogenation at 1 atm. This activity decreases with an increase in the SiO
2/Al
2O
3 ratio from 2.2 to 6.1 and 4.1, i.e. upon going from an X type zeolite to Y and L. For these types of zeolite the activity grows with an increase in Gd
3+ content from 50 to 80%. Oxygen addition to the reaction mixture stabilizes the catalytic activity of zeolites.