The invention is concerned with a transdermal therapeutic system (TTS) comprising buprenorphine and a method of manufacturing such a TTS. The transdermal therapeutic system is used for the transdermal administration of buprenorphine and analogues thereof. In particular, the invention relates to the use of a transdermal therapeutic system (TTS) for analgesic purposes. The TTS according to the invention comprises a transdermal drug delivery composition comprising buprenorphine and an adhesive component, which is a mixture of a crosslinked and a non-crosslinked acrylic polymer and a penetration enhancer comprising a keto acid.