Oligomerization of isobutene has been investigated using several zeolite catalysts to produce triisobutenes that are useful as chemical feedstocks. Stable isobutene conversion and high selectivity for trimers are attained over a beta zeolite with high concentration of Lewis acid sites. Isobutene is quantitatively oligomerized over a beta zeolite with selectivity for trimers > 50% up to 100 h at a high isobutene WHSV of 10 h(-1). Moreover, a deactivated catalyst can be easily regenerated by calcining in flowing air. Zeolite beta's high stability, quantitative conversion, high selectivity, and facile regeneration make it an attractive potential catalyst for isobutene trimerization. (c) 2006 Elsevier Inc. All rights reserved.