Globally, annual spending on anticancer drugs is around US$100 billion, and is predicted to rise to $150 billion by 2020. In the USA, a novel anticancer drug routinely costs more than $100,000 per year of treatment. When adjusted for per capita spending power, however, drugs are most unaffordable in economically developing nations, such as India and China. Not only are launch prices high and rising, but individual drug prices are often escalated during exclusivity periods. High drug prices harm patients - often directly through increased out-of-pocket expenses, which reduce levels of patient compliance and lead to unfavourable outcomes - and harms society - by imposing cumulative price burdens that are unsustainable. Moreover, high drug prices are not readily explained by rational factors, including the extent of benefit patients are likely to derive, the novelty of the agents, or spending on research and development. Herein, we summarize the available empirical evidence on the costs of anticancer drugs, probe the origins and implications of these high costs, and discuss proposed solutions.