The aim of the research described was to study Rb2HPW12O40 as a green and heterogeneous catalyst for the Mannich reaction. One-pot multi-component condensation of an aldehyde, an amine and a ketone at ambient temperature affords the corresponding β-amino ketones using novel nano-sized Rb2HPW12O40. Simple purification, short reaction time and high yield are some of the advantages of this reaction. Also, the catalyst can be readily isolated. The nano catalyst Rb2HPW12O40 has been characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction and scanning electron microscopy.