A needle-exchange programme is a social policy based on the philosophy of harm reduction whereby people can obtain hypodermic needles and syringes without a prescription for little or no cost.

The policy is aimed at intravenous drug addicts. The impact on health of illegal drug use is made more severe by a lack of sterile needles. Needle sharing is a major cause of the spread of certain diseases, notably AIDS and hepatitis C. In the United States a third of all new AIDS cases can be traced to needle sharing and almost 50% of long-term addicts have hepatitis C. The provision of a needle exchange therefore provides a social benefit in reducing health costs and also provides a means to dispose of used needles in a safe manner.

The provision of needle-exchange programmes is opposed by certain groups as weakening the "War on drugs" and encouraging drug use and associated criminality. European studies have not found the provision of needles causes a rise in drug use. In the US the use of federal funds for needle-exchange programmes was banned in 1988 and most states criminalise the possession of needles without a prescription, even so far as to arrest people as they leave private needle-exchange centres.