Organic chlorine compounds constitute a group of more than 2,000 substances which are based on organic compounds (i.e. carbon-containing) with one or more chlorine atoms.

The exceptional reactivity of chlorine enables it to be introduced into virtually all basic substances in organic chemistry. It is also very easy to trace, even in minute quantities. A large number of different products with a wide range of chemical and physical properties can be produced by selecting suitable reaction conditions.

Organic chlorine compounds are important synthetic building blocks in the chemical industry, and they are also formed in nature in large quantities.