To investigate the feasibility of developing a novel melatonin plaster, the effects of vehicles and drug loading dose on the in vitro permeation of melatonin across dorsal hairless mouse skin from pressure-sensitive adhesive (PSA) matrices were examined. Vehicles employed were propylene glycol laurate (PGL), propylene glycol monocaprylate (PGMC) and diethylene glycol monoethyl ether (DGME). Among PSAs used, only $Duro-Tak^{circledR}$ 87-2196 showed a good peeling property. The release from $Duro-Tak^{circledR}$ 87-2196 was proportional to the square root of time, and dose-dependent. The fluxes increased as the loading dose increased over the doses under solubility. The relatively high permeation flux $(3.03{pm}1.37;{mu}g/cm^2/hr)$ was obtained when using PGMC at the melatonin loading dose of $45;mg/140;cm^2$. Lag time was not affected by the vehicles used but by the thickness spread. The melatonin plasters prepared using PGMC showed a good adhesive property onto skin, and showed no crystal formation.