By and large, the entire range of antiretroviral drugs is available anywhere in the world through private channels. Where resources permit, the supply may be adequate and consistent. Through the public sector, however, and for low-income patients, the choice of drugs may be somewhat restricted. This has implications for decisions such as when to start therapy, which therapeutic regimens to use, and what to do when treatment fails. In the context of clinical trials, reliability of supply and quality of drugs is relatively well assured. In the donor-supported projects, despite the subsidised cost of antiretroviral drugs, it is still not unusual for financial constraints to lead to cessation of treatment. In Brazil, a substantial and rapidly increasing proportion of antiretroviral drugs are being produced in the country with considerable cost savings and a positive impact on sustainability of supply.