A wide range of proteins move via vesicular transport across insect gut epithelial cells for release into the hemocoel. The utility of such transcytosed proteins for delivery of insect-specific neurotoxins from the gut into the hemocoel of aphids has recently been demonstrated for the plant lectin, Galanthus nivalis agglutinin (GNA) and for an aphid-transmitted, plant virus coat protein. Proteins that transcytose across the insect gut epithelium allow for appropriate delivery of toxins that are active within the hemocoel, providing a new approach toward development of pest resistant crops. We used an Ussing chamber to examine the efficiencies and transport mechanisms involved with the movement of various proteins across the gut of Spodoptera frugiperda. Test proteins, which included GNA, bovine serum albumin and virus-derived coat proteins, were labeled with fluorescein isothiocyanate or eGFP for ease of detection. There was wide variation in the efficacy of transport of different proteins across the epithelial layer. The mechanisms involved with transport were investigated by addition of inhibitors into the Ussing chamber. Results will be discussed in relation to the potential exploitation of these proteins and pathways for insect pest management.