An efficient and rapid procedure for the synthesis of 2,4-disubstituted-1,3-thiazoles and selenazoles has been described by the reaction of α-bromoketones with thiourea, phenylthiourea and selenourea at ambient temperature in aqueousmediumunder ultrasonic irradiation. Analytically pure products were formed within 10–60 s in excellent yields. The advantageous features of this non-conventional methodology