The purpose of this research was to design and test a functional assay to introduce RNAi into Callinectes sapidus, blue crabs, and knockdown levels of specific mRNA transcription in vivo. Specific proteins investigated were arginine kinase (AK), beta tubulin (b-tub), glyceraldehyde-3-phosphate dehydrogenase (G3PD), Cp 6.1, and Cp8.2. The knockdown levels were tested in a variety of types tissue ranging from autotomized claws, to muscle tissue, gills, hemocytes, heptapancreas, and mid-dorsal hypodermis. This research is still in progress, but there is preliminary data that shows possible knockdown of b-tub and G3PD transcripts. The next proteins of interest for the continuation of this research are cuticle proteins hypothesized to be nucleators involved in calcification of the exoskeleton (Cp6.1 and Cp 8.2) and “heat shock” proteins that will assist in verification of the validity of our RNAi assay design and technique.