The global economic and population growth has significantly increased the demand for fuels. On the other hand, the strictness of environmental legislation and the depreciation of fossil fuel reserves have motivated the research for alternative energy sources. With this purpose, the preparation and characterization of catalysts based on Beta nanozeolites were described in this work, aiming to find active and selective catalysts to produce biofuels through the cracking of crude soybean oil. The samples were prepared by using different organosilanes such as phenylaminopropyltrimethoxysilane (PHAPTMS), phenyltrimethoxysilane (PHMTS) and aminopropyltriethoxysilane (APTES) to functionalize the Beta zeolite seeds. The silanized seeds produced solids with smaller crystallites, more framework aluminum and different textural and acidic properties as compared to the Beta nanozeolite prepared without organosilane. APTES produced the solid with the smallest crystallites while PHAPTMS produced the sample with the highest external area, the differences being related to agglomeration of nanoparticles, generating voids related to the size of organosilane chains. The catalysts showed different selectivities during the cracking of crude soybean oil, depending on the organosilane used in the preparation. This finding was related to the different acidic properties and to the different particles size and porosity of the solids. The Beta nanozeolite obtained without any organosilane produced more gaseous compounds (C2-C4), due to the largest percentage of strong acidic sites, whereas those obtained with organosilanes were more selective to liquid hydrocarbons. The sample prepared with APTES was the most active and selective to hydrocarbons in the range of gasoline, diesel and kerosene, because of its smallest crystallite size and low acidity, as well as to the agglomeration of nanoparticles, which facilitates the hydrogen transfer reactions. Moreover, the sample prepared with PHMTS was the most selective to hydrocarbons in the gasoline range (C5-C11) while that obtained with PHAPTMS was the most selective to oxygenates. These changes were related to the combined effects of crystallite sizes, porosity and acidity on the catalytic properties of the solids, in the different pathways of the complex reaction network of cracking of soybean oil. It was shown that different organosilanes allowed tailoring the catalytic properties of Beta nanozeolites to produce biofuels or chemicals for several applications. (C) 2016 Elsevier B.V. All rights reserved.