Mechanical releases of the predatory mite Phytoseiulus persimilis Athias-Henriot (Acarina: Phytoseiidae) and the predatory bug Orius laevigatus (Fieber) (Heteroptera: Anthocoridae) were carried out in cultivated protected crops (sweet pepper and chrysanthemum), to control the two-spotted spider mite Tetranychus urticae (Koch) and the western flower thrips, Frankliniella occidentalis (Pergande) respectively. Natural enemies were distributed using a newly developed mechanical device compared with manual distribution. The results showed in all experimental trials carried out with the device a greater uniformity of distribution, a reduction of release time and ease of application. In fact, in most of the mechanised plots the predators were regularly recovered, therefore reducing the percentage of leaves infested and their density, so controlling pests sooner than in the manually released ones.