An efficient ultrasound-assisted preparation of a series of novel 4-aryl-3-methyl-4,5-dihydro-1H-pyrazclo[3,4-b]pyridin-6(7H)ones via the reaction of 5-amino-3-methyl-1H-pyrazole, Meldrum's acid and various arylaldehydes using one-pot three-component approach is described. This rapid method produced the products in short reaction times (3-4 min) and excellent yields (87-95%). (C) 2011 Manouchehr Mamaghani. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.