A fruit pitting machine comprises pitting means for removing pits from pit-containing fruit, separator means for effecting relative separation between pitted and unpitted fruit, means for presenting each of a plurality of pieces of fruit successively to the pitting means and to the separator means, a sonic transducer arranged to be struck by a pit removed from a piece of fruit by said pitting means, and control means, controlled by signals from said sonic transducer, for controlling operation of the separator means so as to effect the said relative separation.