The study investigates the activity, selectivity, and stability of dealuminized H-Beta zeolite samples in the oligomerization of pent-1-ene. It was demonstrated that the yield of pentene oligomers primarily depends on the concentration of acid sites in the catalyst. At 110 degrees C, the highest oligomer yield is achieved by an initial H-Beta (33 wt %), while samples subjected to citric acid treatment (H-Beta-1), steam heating (H-Beta-2), and combined treatment (H-Beta-3) are less active in oligomerization, isomers being yielded as the main product. The investigation of the functional dependence of monomer conversion rate and product composition on reaction conditions in the presence of the H-Beta-3 micro/mesoporous sample revealed that the pentene oligomer yield reaches 89% at 200 degrees C, 10 wt % catalyst, and 5 h. Micro/mesoporous zeolites ensure a wider molecular weight distribution of oligomers. The examination of the H-Beta and H-Beta-3 stability in the oligomerization of pent-1-ene identified H-Beta-3 as the most stable sample.