New restrictions on gasoline in some part of the world implies that oxygenates such as MTBE and aromatics should be replaced by other high-octane components. The dimerization of 1-butene, which is a step in the production of "Green" gasoline, is evaluated under liquid phase reaction conditions over acidic Beta zeolites synthesized with different synthesis time. There are substantial differences between Beta zeolites obtained at synthesis times 96 and 240 h leading to different physico-chemical properties and, furthermore, catalytic performances. More acidic Beta zeolites lead to higher yields to light olefins while less acidic samples produce more oligomers, i.e. C12-C14 fraction. Interestingly, it was also observed that strong acid sites catalyze cracking reactions, while the weak ones, oligomerization.