Establishing a breach of the price-fixing prohibitions in Part IV Division 1 of the Competition and Consumer Act 2010(Cth) (‘CCA’) depends on the apparently simple requirement that a ‘contract, arrangement or understanding’ to fix prices can be shown to exist between competitor corporations. However, proof of any such agreement has been problematic for the Australian Competition and Consumer Commission (‘ACCC’) in actions for alleged price-fixing within a range of industries. This article considers the judicial interpretation of the terms ‘contract, arrangement or understanding’ and the type of evidence needed to prove that a price-fixing agreement exists. It also examines the scope and effect of the price-signalling provisions under Part IV Division 1A of the CCA and, in the light of international competition law jurisprudence, contemplates how these provisions may affect the ACCC’s ability to prove price-fixing claims. Possible future directions in this area of the law, resulting from the recommendations of the recent Harper Review, are explored as well.