Porous nanoparticles aggregated from primary zeolite sodium-form Y (NaY) nanocrystals were hydrothermally synthesised using porous precipitated silica as the silica source via a three-stage temperature control strategy, using tetramethylammonium hydroxide (TMAOH) as an organic additive. The synthesised samples were characterised using powder X-ray diffraction, energy dispersive X-ray spectroscopy, nitrogen (N-2) sorption, and particle size analysis. The results show that the zeolite aggregate particles with sizes of 150-600nm were composed of highly crystalline zeolite NaY nanoparticles in the size range of 2-4nm. The particle sizes of porous aggregates can be readily tuned by varying the additive amounts of the zeolite precursor gel without notably changing the sizes of the primary zeolite nanocrystals. The N-2 sorption results show that the zeolite NaY aggregate particles had high microporosity with no clear mesoporosity. The zeolite particles exhibited very good resistance to mechanical conglomeration and remained intact after several months.