Abstract: A transdermal drug delivery device has a drug containing element containing a drug which is preferably charged and first and second electrodes for conducting a current flow through the drug containing element. The current flow causes the drug to be released from the drug containing element and to permeate through the skin of a user to which the device has been fixed. A power source is connected to the first and second electrodes for providing the energy necessary to generate the current flow. The power source comprises a thermocouple or thermopile having two different poles which are connected to the first and/or second electrodes, whereby a self-contained drug delivery device is formed which provides the energy necessary for generating the current flow by means of a difference in temperature of the skin of the user and the ambient air (environment), thus providing a device free of batteries, accumulators or other external energy sources.