The use of chemical pesticides to control stored product insects can be reduced with Integrated Pest Management (IPM) practices such as the use of natural enemies, like parasitoids, to control harmful insects. In this study, improved specifications were developed for shipping containers to deliver healthy beneficial insects to IPM practitioners. Heat transfer through the container walls was evaluated to determine the amount of insulation and natural refrigerant (such as ice) necessary for maintaining the internal temperature in the desirable range throughout the shipping time and was based on recommended temperature limits for commercial shipments. An energy balance on the shipping containers was used to provide the needed design equation to specify the insulation level. Data were obtained from containers with temperature-monitoring sensors when shipped by overnight express from a cooperating supplier's laboratory to GMPRC. Also, standard frozen gels and other potential natural refrigerants were compared in laboratory tests of the containers at times and temperatures comparable to those measured in the experimental shipments. The 0.6% water in dioxane mixture had the best results of the solvents evaluated as refrigerants.