In this study, the aim is to beneficiate magnesite slimes by flotation. In order to achieve flotation for -38 mum magnesite wastes effectively, ultrasonic treatment was utilized simultaneously and as a pre-treatment technique. The results of ultrasonic treatment for magnesite flotation were compared to the results of conventional flotation. As a result, the effects of ultrasound were observed as follows: the froth dimensions became smaller, the froth stability was increased and the froth taking time became longer. Consequently, recovery values also supported the positive effect of ultrasonic treatment for magnesite slimes. (C) 2002 Published by Elsevier Science Ltd.