In recent years, an important intellectual property concept, the ‘doctrine of patent exhaustion’, has received renewed interest in Australia. In Calidad Pty Ltd v Seiko Epson Corporation, the High Court of Australia held that in the absence of a contractual provision to the contrary, a patentee’s rights to control the use of a patented product after its sale are exhausted. This was a landmark decision in the history of Australian patent law, adopted preferably to the ‘doctrine of implied licence’ that has been applied in Australia for more than 100 years. This article aims to analyse how the High Court defined patent exhaustion in Calidad and outlines some of the issues it left unresolved.