Abstract: A transdermal antiemesis system, preferably in the form of a drug-in-adhesive matrix patch, is disclosed comprising an effective antiemesis amount of a selective serotonin (5-HT3) receptor antagonist as an antiemetic incorporated in a skin adhesive composition containing at least one permeation enhancer and a water-insoluble pressure-sensitive adhesive. A preferred antiemetic is granisetron base. The transdermal antiemesis system of this invention provides controlled release of the active antiemetic ingredient from the skin-contacting adhesive formulation of a transderrnal patch, and maintains a sustained transdermal delivery of the antiemetic.