Zeolite-sepiolite inorganic nanoheterostructures have been hydrothermally synthesized by adding a dispersion of colloidal sepiolite to a solution able to produce a nanocrystalline Zeolite (silicalite). The obtained product could be recovered in good yield by simple filtration only when the relative sepiolite concentration exceeded a threshold of 1.8 wt% in the synthesis mixture (amounting to 1: 3 sepiolite: Zeolite wt. ratio in the recovered product). The resulting heterostructures were characterized by XRD, FTIR, thermal (TG-DTA) and chemical analyses, N2 adsorption, TEM, SEM, 29Si NMR, and methylene blue adsorption. The intimate Zeolite-sepiolite interaction at the surface produced a good dispersion of Zeolite particles and prevented their sintering upon calcination to remove the organic structure-directing agent.Experiments in conditions yielding microcrystalline silicalite support the idea that the sepiolite surface acts as nucleation sites for the Zeolite crystallization. The textural properties of the nanoZeolite-sepiolite heterostructure are not a linear combination of their components’.