The short-term effects of harvesting on survival and dispersal of insect predators in hay lucerne (Medicago sativa L.) were investigated in a commercial crop in Australia. Adults of two coleopterans, transverse ladybird beetle (Coccinella transversalis Fabricius Coccinellidae) and pollen beetle (Dicranolaius bellulus (Guérin-Méneville) Melyridae), and one heteropteran, spined predatory shield bug (Oechalia schellembergii (Guérin-Méneville) Pentatomidae), were marked and released into lucerne strips immediately before they were cut for hay. Vacuum sampling of the stubble immediately after harvest showed that proportional mortalities were 0.16, 0.00 and 0.07 respectively. Proportions of the released individuals that were recovered alive were 0.66 for C. transversalis, 0.45 for O. schellembergii and 0.02 for D. bellulus. The proportion of predators that were not recaptured from release areas was greatest for D. bellulus (0.80). To assess dispersal after harvest, 12 strips of lucerne were left uncut within the field in which the marked insects had been released. Intensive sweep-net sampling of these strips caught marked survivors of all three predators. The numbers of insects caught in strips declined with increasing distance from the release point. Many insect predators, therefore, survived harvesting and, if uncut refuge strips are provided, the within-field community of biological control agents is largely preserved.