Abstract: The compositions comprise an effective repellent amount of one or more monoterpenoids, one or more sesquiterpenoids or a blend of one or more monoterpenoids and one or more sesquiterpenoids in combination with a carrier, wherein the compositions are formulated to repel a target pest from a target area. In one embodiment, the one or more monoterpenoids, and/or one or more sesquiterpenoids are from a biorational source, such as a plant volatile. In one embodiment, the one or more sesquiterpenoids are oxygen-containing sesquiterpenoids. In a particular embodiment, the plant volatile is a monoterpenoid, such as “nepetalactone” (or the individual nepetalactone isomers) derived from catnip (Nepeta cataria). In another embodiment, the plant volatile is additionally or alternatively a sesquiterpenoid derived from the fruit of the Osage orange tree (Maclura pomifera), Siam wood or the Amyris plant. Such compositions have repellency, including long term repellency, against arthropods.